Antibody-drug-conjugate and its use for the treatment of cancer

ABSTRACT

The present invention relates to an antibody-drug-conjugate. From one aspect, the invention relates to an anti-body-drug-conjugate comprising an antibody capable of binding to a Target, said antibody being conjugated to at least one drug selected from derivatives of dolastatin 10 and auristatins. The invention also comprises method of treatment and the use of said anti-body-drug-conjugate for the treatment of cancer.

SEQUENCE LISTING

The instant application contains a Sequence Listing which has been submitted electronically in ASCII format and is hereby incorporated by reference in its entirety. Said ASCII copy, submitted on Apr. 16, 2019, is named 03715-0212-02000-SEQLST.txt and is 163,875 bytes in size.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No. 16/385,597, filed on Apr. 16, 2019, now U.S. Pat. No. 11,219,693 B2, which is a divisional application of U.S. patent application Ser. No. 15/306,404, filed on Oct. 24, 2016, now U.S. Pat. No. 10,314,921 B2, which is a national stage filing under 35 U.S.C. § 371 of International Application No. PCT/EP2015/059052, filed on Apr. 27, 2015, which claims priority of European Patent Application No. 14305621.6, filed on Apr. 25, 2014. The contents of these applications are each incorporated herein by reference in their entirety.

The present invention relates to an antibody-drug-conjugate. From one aspect, the invention relates to an antibody-drug-conjugate comprising an antibody capable of binding to a target, said antibody being conjugated to at least one drug selected from derivatives of dolastatin 10 and auristatins. The invention also comprises method of treatment and the use of said antibody-drug-conjugate for the treatment of cancer.

BACKGROUND OF THE INVENTION

The invention relates to an antibody-drug-conjugate (ADC) or conjugate and its use for the treatment of cancer.

ADCs combine the binding specificity of an antibody with the potency of drugs such as, for example, cytotoxic agents. The technology associated with the development of monoclonal antibodies, the use of more effective drugs and the design of chemical linkers to covalently bind these components, has progressed rapidly in recent years.

The use of ADCs allows the local delivery of drugs which, if administered as unconjugated drugs, may result in unacceptable levels of toxicity to normal cells.

In other words, maximal efficacy with minimal toxicity is sought thereby. Efforts to design and refine ADC have focused on the selectivity of antibody as well as drug mechanism of action, drug-linking, drug/antibody ratio (loading or DAR), and drug-releasing properties. Drug moieties may impart their cytotoxic and cytostatic effects by mechanisms including tubulin binding, DNA binding, proteasome, impairment of ribosome function, protein synthesis and/or topoisomerase inhibition. Some cytotoxic drugs tend to be inactive or less active when conjugated to large antibody.

Each antibody must be characterized separately, an appropriate linker designed, and a suitable cytotoxic agent identified that retains its potency upon delivery to tumor cells. One must consider the antigen density on the cancer target and whether normal tissues express the target antigen. Other considerations include whether the entire ADC is internalized upon binding the target; whether a cytostatic or cytotoxic drug is preferable when considering possible normal tissue exposure and/or the type and stage of the cancer being treated; and, whether the linker connecting the antibody to the drug payload is a cleavable or a non-cleavable linkage. Furthermore, the antibody to drug moiety conjugation ratio must be sufficient without compromising the binding activity of the antibody and/or the potency of the drug and without modifying physicochemical properties of the ADC resulting on aggregation or deleterious properties regarding to the future development process of the compound.

An ADC is a complex biological molecule and the challenges to develop an effective ADC remain a significant issue.

SUMMARY OF THE INVENTION

In a first aspect, the present invention is directed to an antibody-drug-conjugate of the following formula (I): Ab-(L-D)_(n)  (I)

or a pharmaceutically acceptable salt thereof,

wherein

Ab is a [Target] antibody or an antigen antibody, or a [Target] binding fragment thereof or an antigen binding fragment thereof;

L is a linker;

D is a drug moiety of the following formula (II):

wherein:

R₁ is H or OH;

R₂ is a group: (C₁-C₆)alkyl, COOH, COO—((C₁-C₆)alkyl) or thiazolyl;

R₃ is H or a (C₁-C₆)alkyl group;

A is:—

-   -   a group of formula -Het-Alk- wherein Alk is a (C₁-C₈)alkanediyl         group and is linked to NR₃, and Het is a heterocycle optionally         substituted by a (C₁-C₆)alkyl group and containing at least one         nitrogen atom, said nitrogen atom being linked to L, or     -   a group of formula -A_(a)-A_(b)- wherein A_(a) is linked to L         and is O or NR₉ with R₉ being H or (C₁-C₆)alkyl and Ab is linked         to NR₃ and is:         -   a (C₁-C₈)alkanediyl group,         -   —(CH₂CH₂X₁)_(a1)(CH₂CH₂X₂)_(a2)(CH₂CH₂X₃)_(a3)(CH₂CH₂X₄)_(a4)CH₂CH₂—             group with X₁, X₂, X₃ and X₄ each independently of one             another representing O or NR₈; a1, a2, a3 and a4 each             independently of one another representing 0 or 1; and R₈             representing H or a (C₁-C₆)alkyl group,         -   an aryl-(C₁-C₈)alkanediyl or heterocycle-(C₁-C₈)alkanediyl             group, said group being optionally substituted by a             (C₁-C₆)alkyl group, the aryl or heterocycle moiety being             linked to A_(a) and the (C₁-C₈)alkanediyl moiety being             linked to NR₃;

the wavy line indicates the point of attachment to L; and

n is 1 to 12.

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein the [Target] or antigen of said [Target] antibody or antigen antibody according to the invention, or a [Target] or an antigen binding fragment thereof, is selected from CD19, CD20, CD22, CD25, CD30, CD33, CD40, CD56, CD64, CD70, CD74, CD79, CD105, CD138, CD174, CD205, CD227, CD326, CD340, MUC16, GPNMB, PSMA, Cripto, ED-B, TMEFF2, EphB2, EphA2, FAP, av integrin, Mesothelin, EGFR, TAG-72, GD2, CAIX, 5T4, HER1, HER3, HER2, IGF-1R, Ax1 and their extra cellular membrane (ECD) fragment.

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein the [Target] or antigen of said [Target] antibody or antigen antibody according to the invention, or a [Target] or an antigen binding fragment thereof, is selected from the HER2, the IGF-1R and the protein Ax1, preferably the human HER2, human IGF-1R and the human protein Ax1, and their extra cellular membrane (ECD) fragment.

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein said Ab is an antibody, or an antigen binding fragment thereof, capable of binding to the human IGF-1R selected from:

i) the antibodies 208F2, 212A11, 214F8, 219D6 and 213B10;

ii) the antibodies which compete for binding to IGF-1R with the antibodies of i); and

iii) the antibodies which bind to the same epitope of IGF-1R as the antibodies of i).

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein said Ab is an antibody, or an antigen binding fragment thereof, capable of binding to the human IGF-1R selected from:

i) an antibody which comprises the three heavy chain CDRs of sequence SEQ ID NOs:

1, 2 and 3 and the three light chain CDRs of sequence SEQ ID NOs: 4, 5 and 6;

ii) an antibody which competes for binding to IGF-1R with the antibody of i); and

iii) an antibody which binds to the same epitope of IGF-1R as the antibody of i).

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein said Ab is an antibody which comprises:

a) a heavy chain variable domain (VH) of sequence SEQ ID NO: 33 wherein said sequence SEQ ID NO: 33 comprises at least 1 back-mutation selected from the residues 20, 34, 35, 38, 48, 50, 59, 61, 62, 70, 72, 74, 76, 77, 79, 82 or 95; and

b) a light chain variable domain (VL) of sequence SEQ ID NO: 35, wherein said sequence SEQ ID NO: 35 comprises at least 1 back-mutation selected from the residues 22, 53, 55, 65, 71, 72, 77 or 87.

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein said Ab is an antibody, or an antigen binding fragment thereof, capable of binding to the human protein Ax1 selected from:

i) an antibody which comprises the three heavy chain CDRs of sequence SEQ ID NOs: 59, 60 and 61 and the three light chain CDRs of sequence SEQ ID NOs: 56, 57 and 58;

ii) an antibody which competes for binding to Ax1 with the antibody of i); and

iii) an antibody which binds to the same epitope of Ax1 as the antibody of i).

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein said Ab is an antibody, or an antigen binding fragment thereof, capable of binding to the human HER2, preferably consisting of Trastuzumab.

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein L is a linker of the following formula (III):

wherein

L₂ is (C₄-C₁₀)cycloalkyl-carbonyl, (C₂-C₆)alkyl, (C₂-C₆)alkyl-carbonyl,

W is an amino acid unit; w is an integer comprised between 0 and 5;

Y is PAB-carbonyl with PAB being

y is 0 or 1;

the asterisk indicates the point of attachment to D; and

the wavy line indicates the point of attachment to A_(b).

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein L₂ is of the following formula:

wherein

the asterisk indicates the point of attachment to (W)_(w); and

the wavy line indicates the point of attachment to the nitrogen atom of the maleimide moiety.

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein w=0, or w=2 and then (W)_(w) is selected from:

wherein

the asterisk indicates the point of attachment to (Y)_(y); and

the wavy line indicates the point of attachment to L₂.

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein L is selected from:

wherein the asterisk indicates the point of attachment to D, and the wavy line indicates the point of attachment to Ab.

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein A is a group of formula -A_(a)-A_(b)- in which A_(a) is as defined above and Ab is a group:

-   -   phenyl-(C₁-C₂)alkanediyl, or     -   heterocycle-(C₁-C₂)alkanediyl optionally substituted by a         (C₁-C₆)alkyl group (notably unsubstituted), the heterocycle         being a saturated, unsaturated or aromatic ring with 5 or 6         members comprising 1 or 2 nitrogen atoms, chosen in particular         from among pyridine, piperidine and imidazole, and being         preferably a pyridine.

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein A is a group of the following formula:

wherein:

R₉ is as defined above and m is an integer comprised between 1 and 8, and preferably wherein R₉═H or Me and m=1 or 2,

the wavy line indicates the point of attachment to L, and

the asterisk indicates the point of attachment to NR₃.

In an embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, wherein (L-D) is selected from:

wherein the wavy line indicates the point of attachment to Ab.

In another embodiment, the present invention relates to an antibody-drug-conjugate according to the invention, having the formula selected from:

and the pharmaceutically acceptable salts thereof,

wherein Ab is a [Target] antibody or an antigen antibody, or a [Target] binding fragment thereof or an antigen binding fragment thereof.

In an embodiment, and according to the invention, said Ab is a [Target] antibody or an antigen antibody, or a [Target] binding fragment thereof or an antigen binding fragment thereof wherein said [Target] or antigen is selected from CD19, CD20, CD22, CD25, CD30, CD33, CD40, CD56, CD64, CD70, CD74, CD79, CD105, CD138, CD174, CD205, CD227, CD326, CD340, MUC16, GPNMB, PSMA, Cripto, ED-B, TMEFF2, EphB2, EphA2, FAP, av integrin, Mesothelin, EGFR, TAG-72, GD2, CAIX, 5T4, HER1, HER3, HER2, IGF-1R, Ax1 and their extra cellular membrane (ECD) fragment.

In an embodiment, and according to the invention, said Ab is a [Target] antibody or antigen antibody, or a [Target] or an antigen binding fragment thereof, wherein said [Target] or antigen is selected from the HER2, the IGF-1R and the protein Ax1, preferably the human HER2, the human IGF-1R and the human protein Ax1, and their extra cellular membrane (ECD) fragment.

In an embodiment, and according to the invention, said Ab is an antibody, or an antigen binding fragment thereof, and is selected from:

a) an Ab, or an antigen binding fragment thereof, capable of binding to the human IGF-1R selected from:

-   -   i) the antibodies 208F2, 212A11, 214F8, 219D6 and 213B10;     -   ii) the antibodies which compete for binding to IGF-1R with the         antibodies of i); and     -   iii) the antibodies which bind to the same epitope of IGF-1R as         the antibodies of i),         b) an Ab, or an antigen binding fragment thereof, capable of         binding to the human IGF-1R selected from:     -   i) an antibody which comprises the three heavy chain CDRs of         sequence SEQ ID NOs: 1, 2 and 3 and the three light chain CDRs         of sequence SEQ ID NOs: 4, 5 and 6;     -   ii) an antibody which competes for binding to IGF-1R with the         antibody of i); and     -   iii) an antibody which binds to the same epitope of IGF-1R as         the antibody of i),         c) an Ab which comprises:     -   i) a heavy chain variable domain (VH) of sequence SEQ ID NO: 33         wherein said sequence SEQ ID NO: 33 comprises at least 1         back-mutation selected from the residues 20, 34, 35, 38, 48, 50,         59, 61, 62, 70, 72, 74, 76, 77, 79, 82 or 95; and     -   ii) a light chain variable domain (VL) of sequence SEQ ID NO:         35, wherein said sequence SEQ ID NO: 35 comprises at least 1         back-mutation selected from the residues 22, 53, 55, 65, 71, 72,         77 or 87,         d) an Ab, or an antigen binding fragment thereof, capable of         binding to the human protein Ax1 selected from:     -   i) an antibody which comprises the three heavy chain CDRs of         sequence SEQ ID NOs: 59, 60 and 61 and the three light chain         CDRs of sequence SEQ ID NOs: 56, 57 and 58;     -   ii) an antibody which competes for binding to Ax1 with the         antibody of i); and     -   iii) an antibody which binds to the same epitope of Ax1 as the         antibody of i), and

e) an A_(b), or an antigen binding fragment thereof, capable of binding to the human HER2, preferably consisting of Trastuzumab or Pertuzumab.

In an embodiment, and according to the invention, n is 2 or n is 4.

In another embodiment, the present invention is directed to an antibody-drug-conjugate according to the present invention for use as a medicament.

In another embodiment, the present is directed to a composition comprising at least one antibody-drug-conjugate according to the present invention.

In an embodiment, the composition according to the present invention further comprises a pharmaceutically acceptable vehicle.

In another embodiment, the present invention is directed to a composition according to the present invention for use in the treatment of a [Target]—or an antigen-expressing cancer, said [Target]—or an antigen being preferably selected from CD19, CD20, CD22, CD25, CD30, CD33, CD40, CD56, CD64, CD70, CD74, CD79, CD105, CD138, CD174, CD205, CD227, CD326, CD340, MUC16, GPNMB, PSMA, Cripto, ED-B, TMEFF2, EphB2, EphA2, FAP, av integrin, Mesothelin, EGFR, TAG-72, GD2, CAIX, 5T4, HER1, HERS, HER2, IGF-1R, Ax1 and their extra cellular membrane (ECD) fragment, more preferably from the HER2, the IGF-1R and the protein Ax1, also more preferably the human HER2, the human IGF-1R and the human protein Ax1, and their extra cellular membrane (ECD) fragment.

In an embodiment, said [Target]—or antigen-expressing cancer is a cancer chosen from breast, colon, esophageal carcinoma, hepatocellular, gastric, glioma, lung, melanoma, osteosarcoma, ovarian, prostate, rhabdomyosarcoma, renal, thyroid, uterine endometrial cancer, mesothelioma, oral squamous carcinoma, Kaposi sarcoma, acute leukemia, colorectal carcinoma, melanoma, pancreatic ductal adenocarcinoma and any drug resistant cancer.

In an embodiment, the present invention relates to a method for the treatment of a [Target]—or antigen-expressing cancer in a subject in need thereof, comprising administering to the subject an effective amount of at least one antibody-drug-conjugate according to the present invention or of a composition according to the present invention.

DETAILED DESCRIPTION OF THE INVENTION

I—The Antibody (Ab)

The terms “antibody”, “antibodies” “ab”, “MAb” or “immunoglobulin” are used interchangeably in the broadest sense and include monoclonal antibodies, preferably isolated, engineered or recombinant antibodies (e.g., full length or intact monoclonal antibodies), polyclonal antibodies, multivalent antibodies or multispecific antibodies (e.g., bispecific antibodies) and also antibody fragment thereof, so long as they exhibit the desired biological activity.

In an embodiment, the antibody of the invention consists of a recombinant antibody. The term “recombinant antibody” refers to an antibody that results from the expression of recombinant DNA within living cells. A recombinant antibody of the invention is obtained by using laboratory methods of genetic recombination, well known by a person skilled in the art, creating DNA sequences that would not be found in biological organisms.

In another embodiment, the antibody of the invention consists of a chemically synthesized antibody.

More particularly, such a molecule consists of a glycoprotein comprising at least two heavy (H) chains and two light (L) chains inter-connected by disulfide bonds. Each heavy chain comprises a heavy chain variable region (or domain) (abbreviated herein as HCVR or VH) and a heavy chain constant region. The heavy chain constant region comprises three domains, CH1, CH2 and CH3. Each light chain comprises a light chain variable region (abbreviated herein as LCVR or VL) and a light chain constant region. The light chain constant region comprises one domain, CL. The VH and VL regions can be further subdivided into regions of hypervariability, termed complementarity determining regions (CDR), interspersed with regions that are more conserved, termed framework regions (FR). Each VH and VL is composed of three CDRs and four FRs, arranged from amino-terminus to carboxy-terminus in the following order: FR1, CDR1, FR2, CDR2, FR3, CDR3, FR4. The variable regions of the heavy and light chains contain a binding domain that interacts with an antigen. The constant regions of the antibodies may mediate the binding of the immunoglobulin to host tissues or factors, including various cells of the immune system (e.g. effector cells) and the first component (Clq) of the classical complement system.

By “antigen binding fragment” or “target binding fragment” of an antibody according to the invention, it is intended to indicate any peptide, polypeptide, or protein retaining the ability to bind to the target (also generally referred as antigen) of the antibody, and comprising an amino acid sequence of at least 10 contiguous amino acid residues, at least 15 contiguous amino acid residues, at least 20 contiguous amino acid residues, at least 25 contiguous amino acid residues, at least 40 contiguous amino acid residues, at least 50 contiguous amino acid residues, at least 60 contiguous amino residues, at least 70 contiguous amino acid residues, at least contiguous 80 amino acid residues, at least contiguous 90 amino acid residues, at least contiguous 100 amino acid residues, at least contiguous 125 amino acid residues, at least 150 contiguous amino acid residues, at least contiguous 175 amino acid residues, at least contiguous 200 amino acid residues, or at least contiguous 250 amino acid residues of the amino acid sequence of the antibody.

In an embodiment, such “antigen binding fragments” are selected in the group consisting of Fv, scFv (sc for single chain), Fab, F(ab′)₂, Fab′, scFv-Fc fragments or diabodies, or any fragment of which the half-life time would have been increased by chemical modification, such as the addition of poly(alkylene) glycol such as poly(ethylene) glycol (“PEGylation”) (pegylated fragments called Fv-PEG, scFv-PEG, Fab-PEG, F(ab′)₂-PEG or Fab′-PEG) (“PEG” for Poly(Ethylene) Glycol), or by incorporation in a liposome, said fragments having at least one of the characteristic CDRs of the antibody according to the invention. Preferably, said “antigen binding fragments” will be constituted or will comprise a partial sequence of the heavy or light variable chain of the antibody from which they are derived, said partial sequence being sufficient to retain the same specificity of binding as the antibody from which it is descended and a sufficient affinity, preferably at least equal to 1/100, in a more preferred manner to at least 1/10, of the affinity of the antibody from which it is descended, with respect to the target.

By “binding”, “binds”, or the like, it is intended that antibody, or any antigen binding fragment thereof, forms a complex with an antigen that is relatively stable under physiologic conditions. Specific binding can be characterized by an equilibrium dissociation constant of at least about 1.10⁻⁶ M. Methods for determining whether two molecules bind are well known in the art and include, for example, equilibrium dialysis, surface plasmon resonance, radiolabelled assays and the like. For the avoidance of doubt, it does not mean that the said antibody could not bind or interfere, at a low level, to another antigen. Nevertheless, as a preferred embodiment, the said antibody binds only to the said antigen.

As used in the present specification, the expression “[Target] antibody” should be interpreted as similar to “anti-[Target] antibody” and means an antibody capable of binding to the [Target].

The expression “Target” or [Target] shall be interpreted as any molecule present at the surface of cells, preferably tumoral cells, more preferably mamals and human cells, and which can be used for drug delivery. Preferably, the Target is specifically express or overexpress on the surface of tumoral cells in comparison with normal cells.

More particularly, the Target can be selected from CD19, CD20, CD22, CD25, CD30, CD33, CD40, CD56, CD64, CD70, CD74, CD79, CD105, CD138, CD174, CD205, CD227, CD326, CD340, MUC16, GPNMB, PSMA, Cripto, ED-B, TMEFF2, EphB2, EphA2, FAP, av integrin, Mesothelin, EGFR, TAG-72, GD2, CAIX, 5T4, HER1, HER3, HER2, IGF-1R or Ax1 (B.A. Teicher, Current Cancer Drug Targets, 2009, 9, 982-1004).

As preferred Target, it can be mentioned HER2, IGF-1R and Ax1, preferably human HER2, IGF-1R and Ax1.

As non limitative example, the expression “HER2 antibody”, “IGF-1R antibody” or “Ax1 antibody” should be interpreted as similar to “anti-HER2 antibody”, “anti-IGF-1R antibody” or “anti-Ax1 antibody” and means an antibody capable of binding to HER2, IGF-1R or Ax1, respectively.

In the present application, the epitope of the antibody is preferentially localized into the extracellular domain of the Target.

In a particular embodiment, the antibody, or any antigen binding fragment thereof, is capable of binding to the Target with an EC₅₀ comprised between 10.10⁻¹⁰ to 1×10⁻¹⁰, and more preferentially between 8×10⁻¹⁰ to 2×10⁻¹⁰.

The term half maximal effective concentration (EC₅₀) corresponds to the concentration of a drug, antibody or toxicant which induces a response halfway between the baseline and maximum after some specified exposure time. It is commonly used as a measure of drug's potency. The EC₅₀ of a graded dose response curve therefore represents the concentration of a compound where 50% of its maximal effect is observed. The EC₅₀ of a quantal dose response curve represents the concentration of a compound where 50% of the population exhibits a response, after specified exposure duration. Concentration measures typically follow a sigmoidal curve, increasing rapidly over a relatively small change in concentration. This can be determined mathematically by derivation of the best-fit line.

As a preferred embodiment, the EC₅₀, determined in the present invention, characterizes the potency of antibody to bind on the Target ECD exposed on human tumor cells. The EC₅₀ parameter is determined using FACS analysis. The EC₅₀ parameter reflects the antibody concentration for which 50% of the maximal binding on the human Target expressed on tumor cells is obtained. Each EC₅₀ value was calculated as the midpoint of the dose response curve using a four-parameter regression curve fitting program (PRISM Software). This parameter has been selected as to be representative of physiological/pathological conditions.

The term “epitope” is a region of an antigen that is bound by an antibody. Epitopes may be defined as structural or functional. Functional epitopes are generally a subset of the structural epitopes and have those residues that directly contribute to the affinity of the interaction. Epitopes may also be conformational, that is, composed of non-linear amino acids. In certain embodiments, epitopes may include determinants that are chemically active surface groupings of molecules such as amino acids, sugar side chains, phosphoryl groups, or sulfonyl groups, and, in certain embodiments, may have specific three-dimensional structural characteristics, and/or specific charge characteristics.

The competition for binding to the Target can be determined by any methods or techniques known by the person skilled in the art such as, without limitation, radioactivity, BIACORE, ELISA, Flow cytometry, etc. As “which competes for binding to the Target” it is meant a competition of at least 20%, preferentially at least 50% and more preferentially at least 70%.

The determination of the binding to the same epitope can be determined by any methods or techniques known by the person skilled in the art such as, without limitation in the examples, radioactivity, BIACORE, ELISA, Flow cytometry. As “which bind to the same epitope of the Target”, it is meant a competition of at least 20%, preferentially at least 50% and more preferentially at least 70%.

As above mentioned, and contrary to the general knowledge, the present invention focuses on specific antibodies presenting a high ability to be internalized following their binding to the Target. As used herein, an antibody that “is internalized” or that “internalized” (the two expressions being similar) is one that is taken up by (meaning it “enters”) the cell upon binding to the Target on a mammalian cell. Such an antibody is interesting as part of the ADC, so it addresses the linked cytotoxic into the targeted cancer cells. Once internalized the cytotoxic triggers cancer cell death.

Important keys to success with ADC therapy are thought to be the target antigen specificity and the internalization of the antigen-antibody complexes into the cancer cells. Obviously non-internalizing antigens are less effective than internalizing antigens to delivers cytotoxic agents. Internalization processes are variable across antigens and depend on multiple parameters that can be influenced by antibodies.

In the ADC, the cytotoxic confers the cytotoxic activity and the used antibody is responsible for the specificity against cancer cells, as well as a vector for entering within the cells to correctly address the cytotoxic. Thus to improve the ADC, the antibody must exhibit high ability to internalize into the targeted cancer cells. The efficiency of the antibody mediated internalisation differs significantly depending on the epitope targeted. Selection of potent internalizing antibodies requires various experimental data studying not only the Target downregulation but also following the antibody penetration into the cells.

In a preferred embodiment, the internalization of the antibody according to the invention can be evaluated by immunofluorescence or FACS (Flow Cytometry) (as exemplified hereinafter in the present application) or any method or process known by the person skilled in the art specific for the internalization mechanism. In a preferred embodiment, the antibody according to the invention can induce internalization after binding to the Target of at least 30%, preferentially 50% and more preferentially 80%.

The complex Target/antibody is internalized after binding of the antibody to the ECD of said Target, and a reduction in the quantity of Target at the surface of the cells is induced. This reduction can be quantified by any method known by the person skilled in the art (western-blot, FACS, immunofluorescence, etc).

In one embodiment, this reduction, thus reflecting the internalization, can be preferably measured by FACS and expressed as the difference or delta between the Mean Fluorescence Intensity (MFI) measured at 4° C. with the MFI measured at 37° C. after 4 hours incubation with the antibody.

As non limitative example, this delta is determined based on MFIs obtained with untreated cells and cells treated with the antibody using i) cancer cells, such as for example MCF, 7 after a 4 hour incubation period with the antibody herein described and ii) a secondary antibody labelled with ALEXA FLUOR 488. This parameter is defined as calculated with the following formula: Δ(MFL_(4° C.)-MFI_(37° c.)) Other embodiments will be detailed in the following examples.

This difference between MFIs reflects the Target downregulation as MFIs are proportional to Target expressed on the cell-surface.

In an advantageous aspect, the antibodies consist of antibodies triggering, as an example, a Δ(MFI_(4° c.)-MFI_(37° c.)) on cancer cell, such as MCF-7, of at least 280, preferably of at least 400.

In more details, the above mentioned delta can be measured according to the following process, which must be considered as an illustrative and non limitative example:

-   -   a) Treating and incubating tumor cells of interest with the         antibody of the invention in either cold (4° C.) or warm (37°         C.) complete culture medium;     -   b) Treating the treated cells of step a) and, in parallel,         untreated cells with a secondary antibody;     -   c) Measuring the MFI (representative of the quantity of IGF-1R         present at the surface) for the treated and the non treated         cells with a secondary labeled antibody capable of binding to         the antibody of the invention; and     -   d) Calculating the delta as the subtraction of the MFI obtained         with the treated cells from the MFI obtained with the non         treated cells.

From this delta MFI, an internalization percentage can be determined as: 100×(MFI_(4° C.)-MFI_(37° C.))/MFI₄° C. .

The antibodies, according to the invention, present, preferably, an internalization percentage comprised between 50% and 99%, 70% and 90%, preferentially between 75% and 87%.

A particular advantage of the antibodies herein described relies on their rate of internalization.

It is generally known that, for an ADC, it is desirable that the used antibodies exhibit a rapid rate of internalization, preferably within 24 hours from administration of the antibody and, more preferably within 12 hours and, even more preferably within 6 hours.

In the present invention, the internalization rate, also referred as cell surface bound antibody decrease or cell surface antibody decay, is expressed as t1/2 (half life) and corresponds as the time necessary to obtain a decrease of 50% of the ΔMFI (this aspect will be clearly understood regarding the following examples).

A particular advantage is that the antibodies of the invention have a t1/2 comprised between 5 and 25 minutes, and preferentially between 10 and 20 minutes.

In the following specificiation, two preferred Target will be exemplified.

For these two preferred Target, by “antibody according to the invention” or “antibody of the invention” it must be understood: “antibody of the ADC according to the invention” or “antibody of the ADC of the invention” respectively.

I.1: IGF-1R antibodies

A particular embodiment of the invention relates to an ADC wherein the antibody Ab comprises three heavy chain CDRs with CDR-H2 of sequence SEQ ID NO: 2 and CDR-H3 of sequence SEQ ID NO: 3, and three light chain CDRs with CDR-L2 of sequence SEQ ID NO: 5.

A particular embodiment of the invention relates to an ADC wherein the antibody Ab comprises the three heavy chain CDRs of sequences SEQ ID NOs: 1, 2 and 3 and the three light chain CDRs of sequences SEQ ID NOs: 4, 5 and 6.

An embodiment of the ADC comprises an antibody comprising the three heavy chain CDRs comprising the sequences SEQ ID NOs: 1, 2 and 3, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 1, 2 and 3; and the three light chain CDRs comprising the sequences SEQ ID NOs: 4, 5 and 6, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 4, 5 and 6.

In another embodiment, the antibody, or any antigen binding fragment thereof, comprises the three light chain CDRs comprising the sequences SEQ ID NOs: 1, 2 and 3; and the three heavy chain CDRs comprising the sequences SEQ ID NOs: 4, 5 and 6.

The IMGT unique numbering has been defined to compare the variable domains whatever the antigen receptor, the chain type, or the species [Lefranc M.-P., Immunology Today 18, 509 (1997)/Lefranc M.-P., The Immunologist, 7, 132-136 (1999)/Lefranc, M.-P., Pommié, C., Ruiz, M., Giudicelli, V., Foulquier, E., Truong, L., Thouvenin-Contet, V. and Lefranc, Dev. Comp. Immunol., 27, 55-77 (2003)]. In the IMGT unique numbering, the conserved amino acids always have the same position, for instance cystein 23 (1st-CYS), tryptophan 41 (CONSERVED-TRP), hydrophobic amino acid 89, cystein 104 (2nd-CYS), phenylalanine or tryptophan 118 (J-PHE or J-TRP). The IMGT unique numbering provides a standardized delimitation of the framework regions (FR1-IMGT: positions 1 to 26, FR2-IMGT: 39 to 55, FR3-IMGT: 66 to 104 and FR4-IMGT: 118 to 128) and of the complementarity determining regions: CDR1-IMGT: 27 to 38, CDR2-IMGT: 56 to 65 and CDR3-IMGT: 105 to 117. As gaps represent unoccupied positions, the CDR-IMGT lengths (shown between brackets and separated by dots, e.g. [8.8.13]) become crucial information. The IMGT unique numbering is used in 2D graphical representations, designated as IMGT Colliers de Perles [Ruiz, M. and Lefranc, M.-P., Immunogenetics, 53, 857-883 (2002)/Kaas, Q. and Lefranc, M.-P., Current Bioinformatics, 2, 21-30 (2007)], and in 3D structures in IMGT/3Dstructure-DB [Kaas, Q., Ruiz, M. and Lefranc, M.-P., T cell receptor and MHC structural data. Nucl. Acids. Res., 32, D208-D210 (2004)].

It must be understood that, without contradictory specification in the present specification, complementarity-determining regions or CDRs, mean the hypervariable regions of the heavy and light chains of immunoglobulins as defined according to the IMGT numbering system.

Nevertheless, CDRs can also be defined according to the Kabat numbering system (Kabat et al., Sequences of proteins of immunological interest, 5^(th) Ed., U.S. Department of Health and Human Services, NIH, 1991, and later editions). There are three heavy chain CDRs and three light chain CDRs. Here, the terms “CDR” and “CDRs” are used to indicate, depending on the case, one or more, or even all, of the regions containing the majority of the amino acid residues responsible for the antibody's binding affinity for the antigen or epitope it recognizes. In order to simplify the reading of the present application, the CDRs according to Kabat are not defined. Nevertheless, it would be obvious for the person skilled in the art, using the definition of the CDRs according to IMGT, to define the CDRs according to Kabat.

In the sense of the present invention, the “identity” or “percentage identity” between two sequences of nucleic acids or amino acids means the percentage of identical nucleotides or amino acid residues between the two sequences to be compared, obtained after optimal alignment, this percentage being purely statistical and the differences between the two sequences being distributed randomly along their length. The comparison of two nucleic acid or amino acid sequences is traditionally carried out by comparing the sequences after having optimally aligned them, said comparison being able to be conducted by segment or by using an “alignment window”. Optimal alignment of the sequences for comparison can be carried out, in addition to comparison by hand, by means of the local homology algorithm of Smith and Waterman (1981) [Ad. App. Math. 2:482], by means of the local homology algorithm of Neddleman and Wunsch (1970) [J. Mol. Biol. 48:443], by means of the similarity search method of Pearson and Lipman (1988) [Proc. Natl. Acad. Sci. USA 85:2444] or by means of computer software using these algorithms (GAP, BESTFIT, FASTA and TFASTA in the Wisconsin Genetics Software Package, Genetics Computer Group, 575 Science Dr., Madison, Wis., or by the comparison software BLAST NR or BLAST P).

Percentage identity is calculated by determining the number of positions at which the amino acid nucleotide or residue is identical between the two sequences, preferably between the two complete sequences, dividing the number of identical positions by the total number of positions in the alignment window and multiplying the result by 100 to obtain the percentage identity between the two sequences.

For example, the BLAST program, “BLAST 2 sequences” (Tatusova et al., “Blast 2 sequences—a new tool for comparing protein and nucleotide sequences”, FEMS Microbiol., 1999, Lett. 174:247-250) available on the site <http://www.ncbi.nlm nih.gov/gorf/b12.html>, can be used with the default parameters (notably for the parameters “open gap penalty”: 5, and “extension gap penalty”: 2; the selected matrix being for example the “BLOSUM 62” matrix proposed by the program); the percentage identity between the two sequences to compare is calculated directly by the program.

For the amino acid sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with a reference amino acid sequence, preferred examples include those containing the reference sequence, certain modifications, notably a deletion, addition or substitution of at least one amino acid, truncation or extension. In the case of substitution of one or more consecutive or non-consecutive amino acids, substitutions are preferred in which the substituted amino acids are replaced by “equivalent” amino acids. Here, the expression “equivalent amino acids” is meant to indicate any amino acids likely to be substituted for one of the structural amino acids without however modifying the biological activities of the corresponding antibodies and of those specific examples defined below.

Equivalent amino acids can be determined either on their structural homology with the amino acids for which they are substituted or on the results of comparative tests of biological activity between the various antibodies likely to be generated.

As a non-limiting example, table 1 below summarizes the possible substitutions likely to be carried out without resulting in a significant modification of the biological activity of the corresponding modified antibody; inverse substitutions are naturally possible under the same conditions.

TABLE 1 Original residue Substitution(s) Ala (A) Val, Gly, Pro Arg (R) Lys, His Asn (N) Gln Asp (D) Glu Cys (C) Ser Gln (G) Asn Glu (E) Asp Gly (G) Ala His (H) Arg Ile (I) Leu Leu (L) Ile, Val, Met Lys (K) Arg Met (M) Leu Phe (F) Tyr Pro (P) Ala Ser (S) Thr, Cys Thr (T) Ser Trp (W) Tyr Tyr (Y) Phe, Trp Val (V) Leu, Ala

A particular aspect of the invention is that the antibody, does not bind to the Insulin receptor (IR). This aspect is of interest as the antibody herein described will not have any negative impact on the IR, meaning the Insulin metabolism.

Still another advantageous aspect of the antibody of the ADC of the invention is that it is capable of binding not only to the human IGF-1R but also to the monkey IGF-1R, and more particularly to the cynomolgus IGF-1R. This aspect is also of interest as it will facilitate the toxicity assessment required for clinical trials.

In still another embodiment, the antibody of the ADC of the invention consists of a monoclonal antibody.

The term “monoclonal antibody” or “Mab” as used herein refers to an antibody obtained from a population of substantially homogeneous antibodies, i.e. the individual antibodies of the population are identical except for possible naturally occurring mutations that may be present in minor amounts. Monoclonal antibodies are highly specific, being directed against a single epitope. Such monoclonal antibody may be produced by a single clone of B cells or hybridoma. Monoclonal antibodies may also be recombinant, i.e. produced by protein engineering or chemical synthesis. Monoclonal antibodies may also be isolated from phage antibody libraries. In addition, in contrast with preparations of polyclonal antibodies which typically include various antibodies directed against various determinants, or epitopes, each monoclonal antibody is directed against a single epitope of the antigen.

The monoclonal antibody herein includes murine, chimeric and humanized antibody, such as described after.

The antibody is preferably derived from an hybridoma of murine origin filed within the French collection for microorganism cultures (CNCM, Pasteur Institute, 25 Rue du Docteur Roux, 75724 Paris Cedex 15, France), said hybridoma being obtained by the fusion of Balb/C immunized mice splenocytes/lymphocytes and cells of the myeloma Sp 2/O-Ag 14 cell line.

In an embodiment, the IGF-1R antibody of the ADC of the invention consists of a murine antibody, then referred to as m[name of the antibody].

In an embodiment, the IGF-1R antibody consists of a chimeric antibody, then referred to as c[name of the antibody].

In an embodiment, the IGF-1R antibody consists of a humanized antibody, then referred to as hz[name of the antibody].

For the avoidance of doubt, in the following specification, the expressions “IGF-1R antibody” and “[name of the antibody]” are similar and include (without contrary specification) the murine, the chimeric and the humanized versions of the said IGF-1R antibody or of the said “[name of the antibody]”. When necessary, the prefix m-(murine), c-(chimeric) or hz-(humanized) is used.

For more clarity, the following table 2 illustrates the CDR sequences, defined according to IMGT, for the preferred antibodies.

TABLE 2 Heavy chain Light chain SEQ ID NO Consensus CDR-H1 1 CDR-H2 2 CDR-H3 3 CDR-L1 4 CDR-L2 5 CDR-L3 6 208F2 CDR-H1 7 CDR-H2 2 CDR-H3 3 CDR-L1 9 CDR-L2 5 CDR-L3 11 212A11 CDR-H1 7 CDR-H2 2 CDR-H3 3 CDR-L1 10 CDR-L2 5 CDR-L3 11 214F8 CDR-H1 7 & CDR-H2 2 213810 CDR-H3 3 CDR-L1 9 CDR-L2 5 CDR-L3 12 219D6 CDR-H1 8 CDR-H2 2 CDR-H3 3 CDR-L1 9 CDR-L2 5 CDR-L3 11

It will be obvious for the man skilled in the art that any combination of 6 CDRs as above described should be considered as part of the present invention.

As can be observed from this table 2, all the antibodies herein described have the same sequences for the CDR-H2, CDR-H3 and CDR-L2, this property being of particular interest as above described.

A specific aspect relates to a murine antibody characterized in that said antibody also comprises light chain and heavy chain constant regions derived from an antibody of a species heterologous with the mouse, notably man.

Another specific aspect relates to a chimeric (c) antibody characterized in that said antibody also comprises light chain and heavy chain constant regions derived from an antibody of a species heterologous with the mouse, notably human.

A chimeric antibody is one containing a natural variable region (light chain and heavy chain) derived from an antibody of a given species in combination with constant regions of the light chain and the heavy chain of an antibody of a species heterologous to said given species.

The chimeric antibodies can be prepared by using the techniques of recombinant genetics. For example, the chimeric antibody could be produced by cloning recombinant DNA containing a promoter and a sequence coding for the variable region of a nonhuman monoclonal antibody of the ADC of the invention, notably murine, and a sequence coding for heterologous species antibody constant region, preferably human. A chimeric antibody the ADC according to the invention coded by one such recombinant gene could be, for example, a mouse-human chimera, the specificity of this antibody being determined by the variable region derived from the murine DNA and its isotype determined by the constant region derived from human DNA.

In a preferred, but not limitative, embodiment, the antibody of the ADC of the invention is selected from:

a) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 13 or any sequence exhibiting at least 80% identity with SEQ ID NO: 13 and the three light chain CDRs of sequences SEQ ID NOs: 9, 5 and 11;

b) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 14 or any sequence exhibiting at least 80% identity with SEQ ID NO: 14 and the three light chain CDRs of sequences SEQ ID NOs: 10, 5 and 11;

c) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 15 or any sequence exhibiting at least 80% identity with SEQ ID NO: 15 and the three light chain CDRs of sequences SEQ ID NOs: 9, 5 and 12;

d) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 16 or any sequence exhibiting at least 80% identity with SEQ ID NO: 16 and the three light chain CDRs of sequences SEQ ID NOs: 9, 5 and 11; and

e) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 17 or any sequence exhibiting at least 80% identity with SEQ ID NO: 17 and the three light chain CDRs of sequences SEQ ID NOs: 9, 5 and 12.

By “any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 13 to 17”, its is intended to designate the sequences exhibiting the three heavy chain CDRs SEQ ID NOs: 1, 2 and 3 and, in addition, exhibiting at least 80%, preferably 85%, 90%, 95% and 98%, identity with the full sequence SEQ ID NO: 13 to 17 outside the sequences corresponding to the CDRs (i.e. SEQ ID NOs: 1, 2 and 3).

In another preferred, but not limitative, embodiment, the antibody of the ADC of the invention is selected from:

a) an antibody comprising a light chain variable domain of sequence SEQ ID NO: 18 or any sequence exhibiting at least 80% identity with SEQ ID NO: 18 and the three heavy chain CDRs of sequences SEQ ID NOs: 7, 2 and 3;

b) an antibody comprising a light chain variable domain of sequence SEQ ID NO: 19 or any sequence exhibiting at least 80% identity with SEQ ID NO: 19 and the three heavy chain CDRs of sequences SEQ ID NOs: 7, 2 and 3;

c) an antibody comprising a light chain variable domain of sequence SEQ ID NO: 20 or any sequence exhibiting at least 80% identity with SEQ ID NO: 20 and the three heavy chain CDRs of sequences SEQ ID NOs: 7, 2 and 3;

d) an antibody comprising a light chain variable domain of sequence SEQ ID NO: 21 or any sequence exhibiting at least 80% identity with SEQ ID NO: 21 and the three heavy chain CDRs of sequences SEQ ID NOs: 8, 2 and 3; and

e) an antibody comprising a light chain variable domain of sequence SEQ ID NO: 22 or any sequence exhibiting at least 80% identity with SEQ ID NO: 22 and the three heavy chain CDRs of sequences SEQ ID NOs: 7, 2 and 3.

By “any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 18 to 22”, its is intended to designate the sequences exhibiting the three light chain CDRs SEQ ID NOs: 4, 5 and 6 and, in addition, exhibiting at least 80%, preferably 85%, 90%, 95% and 98%, identity with the full sequence SEQ ID NO: 18 to 22 outside the sequences corresponding to the CDRs (i.e. SEQ ID NOs: 4, 5 and 6).

An embodiment of the invention relates to an ADC wherein Ab is an antibody selected from:

a) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 13 or any sequence exhibiting at least 80% identity with SEQ ID NO: 13 and a light chain variable domain of sequence SEQ ID NO: 18 or any sequence exhibiting at least 80% identity with SEQ ID NO: 18;

b) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 14 or any sequence exhibiting at least 80% identity with SEQ ID NO: 14 and a light chain variable domain of sequence SEQ ID NO: 19 or any sequence exhibiting at least 80% identity with SEQ ID NO: 19;

c) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 15 or any sequence exhibiting at least 80% identity with SEQ ID NO: 15 and a light chain variable domain of sequence SEQ ID NO: 20 or any sequence exhibiting at least 80% identity with SEQ ID NO: 20;

d) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 16 or any sequence exhibiting at least 80% identity with SEQ ID NO: 16 and a light chain variable domain of sequence SEQ ID NO: 21 or any sequence exhibiting at least 80% identity with SEQ ID NO: 21; and

e) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 17 or any sequence exhibiting at least 80% identity with SEQ ID NO: 17 and a light chain variable domain of sequence SEQ ID NO: 22 or any sequence exhibiting at least 80% identity with SEQ ID NO: 22.

Chimeric antibodies herein described can be also characterized by the constant domain and, more particularly, said chimeric antibodies can be selected or designed such as, without limitation, IgG1, IgG2, IgG3, IgM, IgA, IgD or IgE. More preferably, in the context of the present invention, said chimeric antibodies are IgG1 or IgG4.

An embodiment of the invention relates to an ADC wherein Ab is a chimeric antibody comprising variable domains VH and VL as above described in the format IgG1. More preferably, said chimeric antibody comprises a constant domain for the VH of sequence SEQ ID NO: 43 and a Kappa domain for the VL of sequence SEQ ID NO:

An embodiment of the invention relates to an ADC wherein Ab is a chimeric antibody comprising variable domains VH and VL as above described in the format IgG4. More preferably, said chimeric antibody comprises a constant domain for the VH of sequence SEQ ID NO: 44 and a Kappa domain for the VL of sequence SEQ ID NO: 45.

In another preferred, but not limitative, embodiment, the antibody of the ADC of the invention is selected from:

a) an antibody comprising or consisting of a heavy chain of sequence SEQ ID NO: 23 or any sequence exhibiting at least 80% identity with SEQ ID NO: 23 and a light chain of sequence SEQ ID NO: 28 or any sequence exhibiting at least 80% identity with SEQ ID NO: 28;

b) an antibody comprising or consisting of a heavy chain of sequence SEQ ID NO: 24 or any sequence exhibiting at least 80% identity with SEQ ID NO: 24 and a light chain of sequence SEQ ID NO: 29 or any sequence exhibiting at least 80% identity with SEQ ID NO: 29;

c) an antibody comprising or consisting of a heavy chain of sequence SEQ ID NO: 25 or any sequence exhibiting at least 80% identity with SEQ ID NO: 25 and a light chain of sequence SEQ ID NO: 30 or any sequence exhibiting at least 80% identity with SEQ ID NO: 30;

d) an antibody comprising or consisting of a heavy chain of sequence SEQ ID NO: 26 or any sequence exhibiting at least 80% identity with SEQ ID NO: 26 and a light chain of sequence SEQ ID NO: 31 or any sequence exhibiting at least 80% identity with SEQ ID NO: 31; and

e) an antibody comprising or consisting of a heavy chain of sequence SEQ ID NO: 27 or any sequence exhibiting at least 80% identity with SEQ ID NO: 27 and a light chain of sequence SEQ ID NO: 32 or any sequence exhibiting at least 80% identity with SEQ ID NO: 32.

For more clarity, the following table 3 illustrates the sequences of the VH and VL, respectively, for the preferred chimeric antibodies.

TABLE 3 Heavy Chain Light chain SEQ ID NO c208F2 Variable domain (VH) 13 Variable domain (VL) 18 Full length 23 Full length 28 c212A11 Variable domain (VH) 14 Variable domain (VL) 19 Full length 24 Full length 29 c214F8 Variable domain (VH) 15 Variable domain (VL) 20 Full length 25 Full length 30 c219D6 Variable domain (VH) 16 Variable domain (VL) 21 Full length 26 Full length 31 c213B10 Variable domain (VH) 17 Variable domain (VL) 72 Full length 27 Full length 32

Yet another specific aspect of the present invention relates to an ADC wherein Ab is a humanized antibody characterized in that the constant regions of the light chain and the heavy chain derived from human antibody are, respectively, the lambda or kappa region and the gamma-1, gamma-2 or gamma-4 region.

“Humanized antibodies” means an antibody that contains CDR regions derived from an antibody of nonhuman origin, the other parts of the antibody molecule being derived from one (or several) human antibodies. In addition, some of the skeleton segment residues (called FR) can be modified to preserve binding affinity.

The humanized antibodies or fragments of same can be prepared by techniques known to a person skilled in the art. Such humanized antibodies are preferred for their use in methods involving in vitro diagnoses or preventive and/or therapeutic treatment in vivo. Other humanization techniques, also known to a person skilled in the art, such as, for example, the “CDR grafting” technique described by PDL in patents EP 0 451 216, EP 0 682 040, EP 0 939 127, EP 0 566 647 or U.S. Pat. Nos. 5,530,101, 6,180,370, 5,585,089 and 5,693,761. U.S. Pat. Nos. 5,639,641 , 6,054,297, 5,886,152 and 5,877,293 can also be cited.

As a particular embodiment of the invention, and as it will be explicated in more details in the examples after, it is herein described an antibody consisting of the hz208F2. Such humanization can also be applied to the other antibodies part of the present invention.

In a preferred embodiment, the antibody of the ADC according to the present invention comprises a heavy chain variable domain (VH) having:

i) the CDR-H1, CDR-H2 and CDR-H3 of sequences SEQ ID NOs: 7, 2 and 3, respectively, and

ii) the FR1, FR2 and FR3 derived from the human germline IGHV1-46*01 (SEQ ID NO: 46), and

iii) the FR4 derived from the human germline IGHJ4*01 (SEQ ID NO: 48).

In a preferred embodiment, the antibody of the ADC according to the present invention comprises a light chain variable domain (VL) having:

i) the CDR-L1, CDR-L2 and CDR-L3 of sequences SEQ ID NOs: 9, 5 and 11, respectively, and

ii) the FR1, FR2 and FR3 derived from the human germline IGKV1-39*01 (SEQ ID NO: 47), and

iii) the FR4 derived from the human germline IGKJ4*01 (SEQ ID NO: 49).

In a preferred, but not limitative, embodiment of the invention, the antibody of the ADC comprises:

a) a heavy chain having CDR-H1, CDR-H2 and CDR-H3 of sequences SEQ ID NOs: 7, 2 and 3, respectively, and FR1, FR2 and FR3 derived from the human germline IGHV1-46*01 (SEQ ID NO: 46), and the FR4 derived from the human germline IGHJ4*01 (SEQ ID NO: 48); and

b) a light chain having CDR-L1, CDR-L2 and CDR-L3 of sequences SEQ ID NOs: 9, 5 and 11, respectively, and FR1, FR2 and FR3 derived from the human germline IGKV1-39*01 (SEQ ID NO: 47), and the FR4 derived from the human germline IGKJ4*01 (SEQ ID NO: 49).

In an embodiment, the antibody of the ADC according to the invention comprises a heavy chain variable domain (VH) of sequence SEQ ID NO: 33 and a light chain variable domain (VL) of sequence SEQ ID NO: 35. Said humanized antibody will be called thereinafter hz208F2 (“Variant 1” or “Var. 1”).

In another embodiment, the antibody of the ADC according to the present invention comprises a heavy chain variable domain (VH) of sequence SEQ ID NO: 33 wherein said sequence SEQ ID NO: 33 comprises at least 1 back-mutation selected from the residues 20, 34, 35, 38, 48, 50, 59, 61, 62, 70, 72, 74, 76, 77, 79, 82 or 95.

By the expressions “back-mutation” or “back mutation” it is meant a mutation or replacement of the human residue present in the germline by the corresponding residue initially present in the murine sequence.

In another embodiment, the antibody of the ADC according to the present invention comprises a heavy chain variable domain (VH) of sequence SEQ ID NO: 33 wherein said sequence SEQ ID NO: 33 comprises 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 or 17 back-mutations selected from the residues 20, 34, 35, 38, 48, 50, 59, 61, 62, 70, 72, 74, 76, 77, 79, 82 or 95.

For more clarity, the following table 4 illustrates the preferred back-mutations.

TABLE 4 Residue No. 20 34 35 38 48 50 59 61 62 70 72 74 76 77 79 82 95 Murin M I Y K L W K N E L A K S N A F F humain V M H R M I S A Q M R T T S V E Y

In an embodiment, the antibody of the ADC according to the present invention comprises a light chain variable domain (VL) of sequence SEQ ID NO: 35, wherein said sequence SEQ ID NO: 35 comprises at least 1 back-mutation selected from the residues 22, 53, 55, 65, 71, 72, 77 or 87.

In an embodiment, the antibody of the ADC according to the present invention comprises a light chain variable domain (VL) of sequence SEQ ID NO: 35, wherein said sequence SEQ ID NO: 35 comprises 2, 3, 4, 5, 6, 7 or 8 back-mutations selected from the residues 22, 53, 55, 65, 71, 72, 77 or 87.

In another embodiment, the antibody of the ADC according to the present invention comprises:

a) a heavy chain variable domain (VH) of sequence SEQ ID NO: 33 wherein said sequence SEQ ID NO: 33 comprises at least 1 back-mutation selected from the residues 20, 34, 35, 38, 48, 50, 59, 61, 62, 70, 72, 74, 76, 77, 79, 82 or 95; and

b) a light chain variable domain (VL) of sequence SEQ ID NO: 35, wherein said sequence SEQ ID NO: 35 comprises at least 1 back-mutation selected from the residues 22, 53, 55, 65, 71, 72, 77 or 87.

For more clarity, the following table 5 illustrates the preferred back-mutations.

TABLE 5 Residue No. 22 53 55 65 71 72 77 87 Murin S R H R Y S N F humain T S Q S F T S Y

In such an embodiment, the antibody of the ADC according to the invention comprises all the back-mutations above mentioned and corresponds to an antibody comprising a heavy chain variable domain (VH) of sequence SEQ ID NO: 34 and a light chain variable domain (VL) of sequence SEQ ID NO: 36. Said humanized antibody will be called thereinafter hz208F2 (“Variant 3” or “Var. 3”).

In another embodiment, all the humanized forms comprised between the Variant 1 and the Variant 3 are also encompassed by the present invention. In other words, the antibody of the ADC according to the invention corresponds to an antibody comprising a heavy chain variable domain (VH) of “consensus” sequence SEQ ID NO: 41 and a light chain variable domain (VL) of “consensus” sequence SEQ ID NO: 42. Said humanized antibody, as a whole, will be called thereinafter hz208F2 (“Variant2” or “Var.2”).

In a preferred, but not limitative, embodiment, the antibody of the ADC of the invention is selected from:

a) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 33 or any sequence exhibiting at least 80% identity with SEQ ID NO: 33 and the three light chain CDRs of sequences SEQ ID NOs: 9, 5 and 11; or

b) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 34 or any sequence exhibiting at least 80% identity with SEQ ID NO: 34 and the three light chain CDRs of sequences SEQ ID NOs: 9, 5 and 11.

By “any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 33 or 34”, its is intended to designate the sequences exhibiting the three heavy chain CDRs SEQ ID NOs: 1, 2 and 3 and, in addition, exhibiting at least 80%, preferably 85%, 90%, 95% and 98%, identity with the full sequence SEQ ID NO: 33 or 34 outside the sequences corresponding to the CDRs (i.e. SEQ ID NOs: 1, 2 and 3).

In a preferred, but not limitative, embodiment, the antibody of the ADC of the invention is selected from:

a) an antibody comprising a light chain variable domain of sequence SEQ ID NO: 35 or any sequence exhibiting at least 80% identity with SEQ ID NO: 35 and the three heavy chain CDRs of sequences SEQ ID NOs: 7, 2 and 3; and

b) an antibody comprising a heavy chain variable domain of sequence SEQ ID NO: 36 or any sequence exhibiting at least 80% identity with SEQ ID NO: 36 and the three heavy chain CDRs of sequences SEQ ID NOs: 7, 2 and 3.

By “any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 35 or 36”, its is intended to designate the sequences exhibiting the three light chain CDRs SEQ ID NOs: 4, 5 and 6 and, in addition, exhibiting at least 80%, preferably 85%, 90%, 95% and 98%, identity with the full sequence SEQ ID NO: 35 or 36 outside the sequences corresponding to the CDRs (i.e. SEQ ID NOs: 4, 5 and 6).

Humanized antibodies herein described can be also characterized by the constant domain and, more particularly, said humanized antibodies can be selected or designed such as, without limitation, IgG1, IgG2, IgG3, IgM, IgA, IgD or IgE. More preferably, in the context of the present invention, said humanized antibodies are IgG1 or IgG4.

An embodiment of the invention relates to an ADC wherein Ab is a humanized antibody comprising variable domains VH and VL as above described in the format IgG1. More preferably, said humanized antibody comprises a constant domain for the VH of sequence SEQ ID NO: 43 and a Kappa domain for the VL of sequence SEQ ID NO: 45.

An embodiment of the invention relates to an ADC wherein Ab is a humanized antibody comprising variable domains VH and VL as above described in the format IgG4. More preferably, said humanized antibody comprises a constant domain for the VH of sequence SEQ ID NO: 44 and a Kappa domain for the VL of sequence SEQ ID NO: 45.

Still another embodiment of the invention relates to an ADC wherein Ab is an antibody selected from:

a) an antibody comprising a heavy chain of sequence SEQ ID NO: 37 or any sequence exhibiting at least 80% identity with SEQ ID NO: 37 and a light chain of sequence SEQ ID NO: 39 or any sequence exhibiting at least 80% identity with SEQ ID NO: 39; and

b) an antibody comprising a heavy chain of sequence SEQ ID NO: 38 or any sequence exhibiting at least 80% identity with SEQ ID NO: 38 and a light chain of sequence SEQ ID NO: 40 or any sequence exhibiting at least 80% identity with SEQ ID NO: 40.

For more clarity, the following table 6 illustrates non limitative examples of sequences of the VH and VL for the variant 1 (Var. 1) and the variant 3 (Var. 3) of the humanized antibody hz208F2. It also comprises the consensus sequence for the variant 2 (Var. 2).

TABLE 6 Heavy Chain Light chain SEQ ID NO hz208F2 Variable domain (VH) 33 (var. 1) Variable domain (VL) 35 Full length 37 Full length 39 hz208F2 Variable domain (VH) 34 (Var. 3) Variable domain (VL) 36 Full length 38 Full length 40 hz208F2 Variable domain (VH) 41 (Var. 2) Variable domain (VL) 42

Another aspect of the present invention is an ADC wherein Ab is an antibody selected from i) an antibody produced by the hybridoma 1-4757, 1-4773, 1-4775, 1-4736 or 1-4774 deposited at the CNCM, Institut Pasteur France on the 30 May 2013, 26 Jun. 2013, 26 Jun. 2013, 24 Apr. 2013 and 26 Jun. 2013, respectively, ii) an antibody which competes for binding to IGF-1R with the antibody of i); or iii) an antibody which binds to the same epitope of IGF-1R as does the antibody of i).

It is described herein a murine hybridoma selected from the hybridoma 1-4757, 1-4773, 1-4775, 1-4736 and 1-4774 deposited at the CNCM, Institut Pasteur France on the 30 May 2013, 26 Jun. 2013, 26 Jun. 2013, 24 Apr. 2013 and 26 Jun. 2013, respectively.

It is also described an isolated nucleic acid coding for an antibody, or for an antigen binding fragment thereof, according to the invention.

The terms “nucleic acid”, “nucleic sequence”, “nucleic acid sequence”, “polynucleotide”, “oligonucleotide”, “polynucleotide sequence” and “nucleotide sequence”, used interchangeably in the present description, mean a precise sequence of nucleotides, modified or not, defining a fragment or a region of a nucleic acid, containing unnatural nucleotides or not, and being either a double-strand DNA, a single-strand DNA or transcription products of said DNAs.

The nucleic sequences of the antibodies of the ADC of present invention have been isolated and/or purified, i.e., they were sampled directly or indirectly, for example by a copy, their environment having been at least partially modified. Isolated nucleic acids obtained by recombinant genetics, by means, for example, of host cells, or obtained by chemical synthesis should also be mentioned here.

It is also described a vector comprising a nucleic acid coding for an antibody of the ADC of the invention, or for an antigen binding fragment thereof, according to the invention.

It is disclosed notably targets cloning and/or expression vectors that contain such a nucleotide sequence.

The vectors preferably contain elements which allow the expression and/or the secretion of nucleotide sequences in a given host cell. The vector thus may contain a promoter, translation initiation and termination signals, as well as suitable transcription regulation regions. It must be able to be maintained in a stable manner in the host cell and may optionally have specific signals which specify secretion of the translated protein. These various elements are selected and optimized by a person skilled in the art according to the host cell used. For this purpose, the nucleotide sequences can be inserted in self-replicating vectors within the chosen host or be integrative vectors of the chosen host.

The vectors are, for example, vectors of plasmid or viral origin. They are used to transform host cells in order to clone or express the nucleotide sequences of the invention.

Such vectors are prepared by methods typically used by a person skilled in the art and the resulting clones can be introduced into a suitable host by standard methods such as lipofection, electroporation, conjugation, heat shock or chemical methods.

It is disclosed also isolated host cells transformed by or comprising a vector as above described.

The host cell can be selected among prokaryotic or eukaryotic systems such as bacterial cells, for example, but also yeast cells or animal cells, notably mammal cells (with the exception of human). Insect or plant cells can also be used.

It is also disclosed a method for the production of an antibody according to the invention, or an antigen binding fragment thereof, characterized in that said method comprises the following steps:

a) the culture in a medium with the suitable culture conditions for a host cellas disclosed above; and

b) the recovery of the antibody thus produced from the culture medium or from said cultured cells.

The transformed cells are of use in methods for the preparation of recombinant antibodies. Methods for the preparation of antibodies in recombinant form using a vector and/or a cell transformed by a vector, are also comprised in the present specification. Preferably, a cell transformed by a vector as above described is cultured under conditions that allow the expression of the aforesaid antibody and recovery of said antibody.

As already mentioned, the host cell can be selected among prokaryotic or eukaryotic systems. In particular, it is possible to identify the nucleotide sequences that facilitate secretion in such a prokaryotic or eukaryotic system. A vector according to the invention carrying such a sequence can thus be used advantageously for the production of recombinant proteins to be secreted. Indeed, the purification of these recombinant proteins of interest will be facilitated by the fact that they are present in the supernatant of the cellular culture rather than inside host cells.

The antibody of the ADC of the invention can also be prepared by chemical synthesis. One such method of preparation is also an object of the invention. A person skilled in the art knows methods for chemical synthesis, such as solid-phase techniques or partial solid-phase techniques, by condensation of fragments or by conventional synthesis in solution. Polypeptides obtained by chemical synthesis and capable of containing corresponding unnatural amino acids are also comprised in the invention.

The ADC comprising antibody likely to be obtained by the method above described are also comprised in the present invention.

According to a particular aspect, the invention concerns an ADC wherein Ab is an antibody, or an antigen binding fragment thereof, as above described for use as an addressing vehicle for delivering a cytotoxic agent at a host target site, said host target site consisting of an epitope localized into IGF-1R, preferably the IGF-1R extracellular domain, more preferably the human IGF-1R (SEQ ID NO: 50) and still more preferably the human IGF-1R extracellular domain (SEQ ID NO: 51), and still more preferably to the N-terminal of the human IGF-1R extracellular domain (SEQ ID NO: 52), or any natural variant sequence thereof.

In a preferred embodiment, said host target site is a target site of a mammalian cell, more preferably of a human cell, more preferably cells which naturally or by way of genetic recombination, express IGF-1R.

1.2: Ax1 Antibodies

Without any contradictory indication, the definition or expression used and defined in the paragraph “I.1, IGF-1R antibodies” are the same in the present paragraph and can be applied to all the ADC of the present invention.

The Ax1 antibody is capable of binding to the human protein Ax1. More particularly, the said target is an epitope located into the extracellular domain of Ax1 (referred as the Ax1 ECD for “Ax1 Extra Cellular Domain”).

The Ax1 ECD is a 451 amino acids fragment, corresponding to amino acids 1-451 of the sequence SEQ ID NO: 103, which sequence is represented in the sequence listing as SEQ ID NO: 105 Amino acids 1-25 corresponding to the signal peptide, the ECD of the human protein Ax1 without the signal peptide corresponds to the amino acids 26-451 of the sequence SEQ ID NO: 104, represented by the sequence SEQ ID NO: 106.

The Ax1 antibody of yhe ADC of the invention comprises the three light chain CDRs comprising the sequences SEQ ID NOs: 56, 57 and 58, or any sequence exhibiting at least 90%, preferably 95% and 98% identity with SEQ ID NOs: 56, 57 and 58; and the three heavy chain CDRs comprising the sequences SEQ ID NOs: 59, 60 and 61, or any sequence exhibiting at least 90%, preferably 95% and 98% identity with SEQ ID NOs: 59, 60 and 61.

In an embodiment, the Ax1 antibody comprises the three light chain CDRs comprising respectively the sequences SEQ ID NOs: 56, 57 and 58; and the three heavy chain CDRs comprising respectively the sequences SEQ ID NOs: 59, 60 and 61.

In an embodiment, the Ax1 antibody consists of the m1613F12 comprising i) a light chain variable domain of sequence SEQ ID NO: 62, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 62; and/or ii) a heavy chain variable domain of sequence SEQ ID NO: 63, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 63.

For more clarity, table 7a below summarizes the various amino acid sequences corresponding to the Ax1 antibody.

TABLE 7a CDR numbering Heavy chain Light chain SEQ ID NO 1613F12 IMGT CDR-L1 56 CDR-L2 57 CDR-L3 58 CDR-H1 59 CDR-H2 60 CDR-H3 61 variable domain 62 variable domain 63

In an embodiment, the Ax1 antibody consists of the c1613F12 comprising the three light chain CDRs comprising the sequences SEQ ID NOs: 56, 57 and 58, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 56, 57 and 58; and the three heavy chain CDRs comprising the sequences SEQ ID NOs: 59, 60 and 61, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 59, 60 and 61.

In an embodiment, c1613F12 comprises the three light chain CDRs comprising respectively the sequences SEQ ID NOs: 56, 57 and 58; and the three heavy chain CDRs comprising respectively the sequences SEQ ID NOs: 59, 60 and 61.

In an embodiment, the Ax1 antibody consists of the c1613F12 comprising i) a light chain variable domain of sequence SEQ ID NO: 62, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 62; and/or ii) a heavy chain variable domain of sequence SEQ ID NO: 63, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 63.

In an embodiment, the Ax1 antibody consists of the hz1613F12 comprising the three light chain CDRs comprising the sequences SEQ ID NOs: 56, 57 and 58, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 56, 57 and 58; and the three heavy chain CDRs comprising the sequences SEQ ID NOs: 59, 60 and 61, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 59, 60 and 61.

In an embodiment, hz1613F12 comprises the three light chain CDRs comprising respectively the sequences SEQ ID NOs: 56, 57 and 58; and the three heavy chain CDRs comprising respectively the sequences SEQ ID NOs: 59, 60 and 61.

In an embodiment, hz1613F12 comprises a light chain variable domain consisting of the sequence SEQ ID NO: 70, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 70; and the three heavy chain CDRs consisting of sequences SEQ ID NOs: 59, 60 and 61.

In another embodiment of the invention, hz1613F12 comprises a light chain variable domain of sequence selected in the group consisting of SEQ ID NO: 71 to 81 or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 71 to 81; and the three heavy chain CDRs consisting of SEQ ID NOs: 59, 60 and 61.

In order to illustrate the identity percentage as defined before, by “any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 70 to 81”, its is intended to designate the sequences exhibiting the three light chain CDRs SEQ ID NOs: 56, 57 and 58 and, in addition, exhibiting at least 80%, preferably 85%, 90%, 95% and 98%, identity with the full sequence SEQ ID NO: 70 to 81 outside the sequences corresponding to the CDRs (i.e. SEQ ID NOs: 56, 57 and 58).

For more clarity, table 7b below summarizes the various amino acid sequences corresponding to the humanized Ax1 antibody light chain (VL) of the ADC of the invention (with hz.=humanized)

TABLE 7b Version SEQ ID NO hz1613F12 VL consensus 70 VL1 71 VL1 I2V 72 VL1 M4I 73 VL2.1 74 VL2.1 V49T 75 VL2.1 P50N 76 VL2.2 77 VL2.2 V49T 78 VL2.2 P50N 79 VL2.3 80 VL3 81

In an embodiment, hz1613F12 comprises a heavy chain variable domain consisting of the sequence SEQ ID NO: 82, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 82; and the three light chain CDRs consisting of sequences SEQ ID NOs: 56, 57 and 58.

In another embodiment, hz1613F12 comprises a heavy chain variable domain of sequence selected in the group consisting of SEQ ID NOs: 83 to 102, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 83 to 102; and the three light chain CDRs consisting of SEQ ID NOs: 56, 57 and 58.

In order to illustrate the identity percentage as defined before, by “any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 82 to 102”, its is intended to designate the sequences exhibiting the three heavy chain CDRs SEQ ID NOs: 59, 60 and 61 and, in addition, exhibiting at least 80%, preferably 85%, 90%, 95% and 98%, identity with the full sequence SEQ ID NOs: 82 to 102 outside the sequences corresponding to the CDRs (i.e. SEQ ID NOs: 59, 60 and 61).

For more clarity, table 7c below summarizes the various amino acid sequences corresponding to the humanized antigen binding protein heavy chain (VH) of the invention (with hz.=humanized)

TABLE 7c Version SEQ ID NO hz1613F12 VH consensus 82 VH1 83 VH1 M39I 84 VH1 W55R N66K 85 VH1 I84S 86 VH1 S85N 87 VH1 I84N S85N 88 VH2.1 89 VH2.1 Q3H 90 VH2.1 W55R 91 VH2.1 N66K 92 VH2.1 W55R N66K 93 VH2.1 R80S 94 VH2.1 N66K R80S 95 VH2.2 96 VH2.2 M89L 97 VH2.3 98 VH2.3 W55R 99 VH2.3 Q3H W55R 100 VH2A 101 VH3 102

In an embodiment, hz1613F12 comprises a light chain variable domain of sequence selected in the group consisting of SEQ ID NO: 70 and any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 70; and a heavy chain variable domain of sequence selected in the group consisting of SEQ ID NO: 82 and any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NO: 82.

In an embodiment, hz1613F12 comprises a light chain variable domain of sequence selected in the group consisting of SEQ ID NOs: 71 to 81, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 71 to 81; and a heavy chain variable domain of sequence selected in the group consisting of SEQ ID NOs: 83 to 102, or any sequence exhibiting at least 80%, preferably 85%, 90%, 95% and 98% identity with SEQ ID NOs: 83 to 102.

Another aspect of the present invention is an ADC wherein Ab is an antibody selected from i) an antibody produced by the hybridoma 1-4505, deposited at the CNCM, Institut Pasteur France on the 28 Jul. 2011, ii) an antibody which competes for binding to Ax1 with the antibody of i); or iii) an antibody which binds to the same epitope of Ax1 as does the antibody of i).

According to another aspect, It is disclosed a murine hybridoma selected from the hybridoma 1-4505.

Table 8 below summarizes the nucleotide sequences concerning CDRs of the 1613F12.

TABLE 8 CDR Antibody numbering Heavy chain Light chain SEQ. ID NO 1613F12 IMGT CDR-L1 64 CDR-L2 65 CDR-L3 66 CDR-H1 67 CDR-H2 68 CDR-H3 69

In an embodiment, nucleic acid sequences of the CDRs can be selected from the sequences SEQ ID NOs: 64 to 69.

A non limitative embodiment it is disclosed herein an isolated nucleic acid or a combination thereof coding for an antibody characterized in that said nucleic acid or its combination comprises the 6 CDRs sequences SEQ ID NOs: 64 to 69.

1.3: HER2 Antibodies

The HER2 antibodies can consist of any antibody capable of binding to HER2 such as, without limitation, TRASGEX (Glycotope), Trastuzumab, Pertuzumab or any biosimilar thereof.

In a preferred embodiment, the HER2 antibody is the Trastuzumab (Herceptin®; 4D5; Genentech, San Francisco, Calif.).

II— the Drug (D)

The drug moiety according to the invention has the following formula (II)

wherein:

R₁ is H or OH;

R₂ is a group: (C₁-C₆)alkyl (e.g. methyl), COOH, COO—((C₁-C₆)alkyl) (such as COOMe) or thiazolyl (such as thiazol-2-yl);

R₃ is H or a (C₁-C₆)alkyl group (such as methyl), in particular a (C₁-C₆)alkyl group,

A is:

-   -   a group of formula -Het-Alk- wherein Alk is a (C₁-C₈)alkanediyl         group and is linked to NR₃, and Het is a heterocycle optionally         substituted by a (C₁-C₆)alkyl group and containing at least one         nitrogen atom, said nitrogen atom being linked to L, or     -   a group of formula -A_(a)-A_(b)- wherein A_(a) is linked to L         and is O or NR₉ with R₉ being H or (C₁-C₆)alkyl (such as methyl)         and A_(b) is linked to NR₃ and is:         -   a (C₁-C₈)alkanediyl group (such as —(CH₂)_(m)— with m             comprised between 1 and 8),         -   a             —(CH₂CH₂X₁)_(a1)(CH₂CH₂X₂)_(a2)(CH₂CH₂X₃)_(a3)(CH₂CH₂X₄)_(a4)CH₂CH₂—             group with X₁, X₂, X₃ and X₄ each independently of one             another representing O or NR₈; a1, a2, a3 and a4 each             independently of one another representing 0 or 1 (in             particular with a1+a2+a3+a4=1 or 2, in particular 1); and R₈             representing H or a (C₁-C₆)alkyl group (such as methyl),         -   an aryl-(C₁-C₈)alkanediyl or heterocycle-(C₁-C₈)alkanediyl             group, said group being optionally substituted by a             (C₁-C₆)alkyl group, the aryl or heterocycle moiety being             linked to A_(a) and the (C₁-C₈)alkanediyl moiety being             linked to NR₃;

the wavy line indicates the point of attachment to L.

The radicals R₂, R₃ and A may be chiral groups and may be in the form of their different stereoisomers and optionally in the form of a mixture of stereoisomers.

By «stereoisomer», in the meaning of the present invention is meant a geometric isomer or an optical isomer.

Geometrical isomers result from the different position of the substituents on a double bond which may therefore have a Z or E configuration.

Optical isomers result in particular from the different position in space of the substituents on a carbon atom comprising 4 different substituents. This carbon atom then forms a chiral or asymmetric centre. Optical isomers comprise diastereoisomers and enantiomers. Optical isomers which are images of one another in a mirror but which cannot be superimposed are called «enantiomers». Optical isomers which are not superimposable images of one another in a mirror are called «diastereoisomers».

A mixture containing equal quantities of two individual enantiomer forms of opposite chirality is called a«racemic mixture».

By«alkyl» in the present invention is meant a monovalent linear or branched, saturated hydrocarbon chain. For example, mention can be made of methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl or hexyl groups.

By«(C_(x)-C_(y))alkyl» in the meaning of the present invention is meant an alkyl chain such as defined above comprising x to y carbon atoms. Therefore, a (C₁-C₆)alkyl group is an alkyl chain having 1 to 6 carbon atoms. The (C₁-C₆)alkyl is advantageously a (C₁-C₄)alkyl, preferably a (C₁-C₂)alkyl.

By«alkanediyl» in the present invention is meant a divalent linear or branched, saturated hydrocarbon chain. For example, mention can be made of methanediyl, ethanediyl, propanediyl, butanediyl, pentanediyl, hexanediyle, and the like.

By«(C_(x)-C_(y))alkanediyl» in the meaning of the present invention is meant an alkanediyl chain such as defined above comprising x to y carbon atoms. Therefore, a (C₁-C₈)alkanediyl group is an alkanediyl chain having 1 to 8 carbon atoms.

By«aryl» in the meaning of present invention is meant an aromatic hydrocarbon group preferably having 6 to 10 carbon atoms and able to comprise one or two fused rings. For example a phenyl or a naphthyl can be cited. Advantageously it is a phenyl.

By«heterocycle» in the meaning of present invention is meant a saturated, unsaturated or aromatic hydrocarbon group having 1 or 2 fused rings and in which one or more, advantageously 1 to 4, more advantageously 1 or 2 of the carbon atoms are each replaced by a heteroatom chosen from among oxygen, nitrogen and sulfur. Advantageously the heterocycle comprises 5 to 10 carbon atoms and heteroatoms. For example, mention can be made of furan, pyrrole, thiophene, thiazole, isothiazole, oxadiazole, imidazole, oxazole, isoxazole, pyridine, pyrimidine, piperazine, piperidine, quinazoline, quinoline, quinoxaline, benzofuran, benzothiophene, indoline, indolizine, benzothiazole, benzothiophene, benzopyran, benzoxazole, benzo[1,3]dioxole, benzoisoxazole, benzimidazole, chromane, chromene, dihydrobenzofuran, dihydrobenzothiophene, dihydroisoxazole, isoquinoline, dihydrobenzo[1,4]dioxin, imidazo[1,2-a]pyridine, furo[2,3-c]pyridine, 2,3-dihydro-1H-indene, [1,3]dioxolo[4,5-c]pyridine, pyrrolo[1,2c]pyrimidine, pyrrolo[1,2-a]pyrimidine, tetrahydronaphthalene and benzo[b][1,4]oxazin.

In the present invention, the heterocycle is more particularly a saturated, unsaturated or aromatic ring with 5 to 6 members comprising 1 or 2 nitrogen atoms. For example, mention can be made of pyrrole, imidazole, pyridine, pyrimidine, piperazine and piperidine rings. Preferably it is a pyridine, a piperidine, or an imidazole.

Among the drug moieties of the invention, one particularly appreciated class of drug moieties corresponds to the formula (II) drug moieties in which R₁ is OH and R₂ represents a (C₁-C₆)alkyl group, such as methyl.

Another particularly appreciated class of drug moieties corresponds to the formula (II) drug moieties in which R₁ is a hydrogen and R₂ is a thiazolyl (in particular a thiazol-2-yl group).

Another class of particularly appreciated drug moieties corresponds to the formula (II) drug moieties in which R₁ is a hydrogen and R₂ is a COO—((C₁-C₆)alkyl) group such as COOMe.

Another class of particularly appreciated compounds corresponds to the formula (II) drug moieties in which R₁ is a hydrogen and R₂ is a COOH group.

According to one particular embodiment of the present invention, R₂ is a methyl, COOH, COOMe or thiazol-2-yl group.

Therefore the drug moieties of the invention are advantageously formula (II) drug moieties in which:

-   -   R₁═OH and R₂=Me (methyl), or     -   R₁═H and R₂═COOH, COOMe or thiazol-2-yl.

According to a preferred embodiment, R₁═H and R₂═COOH, COOMe or thiazol-2-yl, preferably R₂═COOH or COOMe, and more preferably R₂═COOH.

R₃ particularly represents H or a methyl group, advantageously a methyl group.

In a preferred embodiment, R₁ is H, R₂ is COOH and R₃ is a methyl group.

In the definition of A:

-   -   the (C₁-C₈)alkanediyl group is advantageously a         (C₁-C₆)alkanediyl group, preferably a (C₁-C₄)alkanediyl group         and more preferably a (C₁-C₂)alkanediyl group, and in particular         it is a straight chain having the formula —(CH₂)_(m)— wherein m         is an integer comprised between 1 and 8, advantageously between         1 and 6, preferably between 1 and 4, more preferably m is 1 or         2,     -   the aryl group is advantageously a phenyl group, and     -   the heterocycle is advantageously a saturated, unsaturated or         aromatic ring with 5 or 6 members having 1 or 2 nitrogen atoms;         for example, a pyrrole, imidazole, pyridine, pyrimidine,         piperazine, or piperidine ring; preferably a pyridine,         piperidine or imidazole; more preferably a pyridine.

When A is a group of formula -Het-Alk-, Het is more particularly a heterocycle chosen among a piperidine and an imidazole.

When A is a group of formula -A_(a)-A_(b)- wherein Ab is a heterocycle-(C₁-C₈)alkanediyl group optionally substituted by a (C₁-C₆)alkyl group, the heterocycle is more particularly a pyridine.

According to a preferred embodiment, A is a group of formula -A_(a)-A_(b)- as defined above.

A_(a) is O or NR₉, and preferably NR₉, with R₉ as defined above, and preferably with R₉═H or Me.

According to a particular embodiment of the invention, Ab represents a group:

-   -   (C₁-C₆)alkanediyl, in particular (C₂-C₆)alkanediyl (such as         —(CH₂)_(m)— with m comprised between 1 and 6, preferably between         2 and 6),     -   —(CH₂CH₂X₁)_(a1)(CH₂CH₂X₂)_(a2)CH₂CH₂— with a1+a2 advantageously         representing 1 or 2, in particular 1,     -   aryl-(C₁-C₆)alkanediyl, or     -   heterocycle-(C₁-C₆)alkanediyl optionally substituted by a         (C₁-C₆)alkyl group (notably unsubstitued).

According to another particular embodiment of the invention, Ab represents a group:

-   -   (C₁-C₄)alkanediyl, in particular (C₂-C₄)alkanediyl (such as         —(CH₂)_(m)— with m comprised between 1 and 4 and preferably         being 2, 3 or 4),     -   —(CH₂CH₂X₁)CH₂CH₂— or —(CH₂CH₂X₁)(CH₂CH₂X₂)CH₂CH₂—     -   aryl-(C₁-C₄)alkanediyl, or     -   heterocycle-(C₁-C₄)alkanediyl optionally substituted by a         (C₁-C₆)alkyl group (notably unsubstitued).

According to another particular embodiment of the invention, Ab represents a group:

-   -   (C₁-C₄)alkanediyl, in particular (C₂-C₄)alkanediyl (such as         —(CH₂)_(m)— with m comprised between 1 and 4 and preferably         being 2, 3 or 4),     -   —(CH₂CH₂X₁)CH₂CH₂—     -   aryl-(C₁-C₂)alkanediyl, or     -   heterocycle-(C₁-C₂)alkanediyl optionally substituted by a         (C₁-C₆)alkyl group (notably unsubstitued).

According to another particular embodiment, Ab represents:

an aryl-(C₁-C₈))alkanediyl group; or a heterocycle-(C₁-C₈)alkanediyl group optionally substituted by a (C₁-C₆)alkyl group (notably unsubstitued);

notably an aryl-(C₁-C₆)alkanediyl group; or a heterocycle-(C₁-C₆)alkanediyl group optionally substituted by a (C₁-C₆)alkyl group (notably unsubstitued);

advantageously an aryl-(C₁-C₄)alkanediyl group; or a heterocycle-(C₁-C₄)alkanediyl group optionally substituted by a (C₁-C₆)alkyl group (notably unsubstitued);

and preferably an aryl-(C₁-C₂)alkanediyl group; or a heterocycle-(C₁-C₂)alkanediyl group optionally substituted by a (C₁-C₆)alkyl group (notably unsubstitued).

According to yet another particular embodiment, Ab is an aryl-(C₁-C₈)alkanediyl group; notably an aryl-(C₁-C₆)alkanediyl group; advantageously an aryl-(C₁-C₄)alkanediyl group; and preferably an aryl-(C₁-C₂)alkanediyl group.

In the above particular embodiments for A_(b), the aryl group is advantageously a phenyl group.

In the above particular embodiments for A_(b), the heterocycle is advantageously a saturated, unsaturated or aromatic ring with 5 or 6 members having 1 or 2 nitrogen atoms. For example, mention can be made of pyrrole, imidazole, pyridine, pyrimidine, piperazine, or piperidine rings. Preferably it is a pyridine, piperidine or imidazole, and more preferably, it is a pyridine.

Advantageously, A_(b) represents a group:

-   -   phenyl-(C₁-C₂)alkanediyl, or     -   heterocycle-(C₁-C₂)alkanediyl optionally substituted by a         (C₁-C₆)alkyl group (notably unsubstitued), the heterocycle being         a saturated, unsaturated or aromatic ring with 5 or 6 members         comprising 1 or 2 nitrogen atoms, chosen in particular from         among pyridine, piperidine and imidazole, and being preferably a         pyridine.

In a preferred embodiment, Ab is a phenyl-(C₁-C₂)alkanediyl group.

According to a preferred embodiment, A has the following formula:

and preferably the following formula:

wherein:

R₉ and m are as defined previously, and preferably with R₉═H or Me and m=1 or 2,

the wavy line indicates the point of attachment to L, and

the asterisk indicates the point of attachment to NR₃.

Advantageously, the drug moiety is chosen from among the following moieties:

Preparation of the Drug (of Formula DH):

The drug can be prepared using the general methods described in the following synthesis schemes, optionally supplemented by any standard operation when needed that is described in the literature or well known to persons skilled in the art, or described in the examples in the experimental part hereof.

Scheme 1 illustrates the first general method which can be used to prepare the drug. In the above general formulas, R₁, R₂ and R₃ are such as previously defined, R₄ represents -AH, and R_(4a) represents a R₄ group such as previously defined optionally in protected form and G is a protective group.

The first step consists of the condensing of compound (II), protected on its amine function by a protective group G, with compound (III). X may represent a leaving group such as a chlorine. In this case the first step consists of the reaction between an acid chloride and an amine. This reaction can be conducted using methods and techniques well known to those skilled in the art. In one particularly appreciated method, the two entities are caused to react in the presence of an organic or inorganic base e.g. Et₃N, iPr₂NEt, pyridine, NaH, Cs₂CO₃, K₂CO₃ in a solvent such as THF, dichloromethane, DMF, DMSO, at a temperature notably between −20° C. and 100° C. X may also be a hydroxyl (OH). In this case, the first step is a condensation reaction between the carboxylic acid (II) and the amine (III). This reaction can be performed following methods and techniques well known to skilled persons. In one particularly appreciated method, these two entities are caused to react in the presence of a coupling agent such as 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide (EDC), 3-hydroxy-1,2,3-benzotriazin-4(3H)-one, a tertiary amine such as diisopropylethylamine, in a polar aprotic solvent such as dichloromethane or DMF, at a temperature notably between −15° C. and 40° C. In another particularly appreciated method, these two entities are caused to react in the presence of diethyl phosphorocyanidate (DEPC), a tertiary amine such as triethylamine, in a polar aprotic solvent such as dichloromethane or DMF, at a temperature of between −15° C. and 40° C. Another particularly appreciated method consists of causing these two entities to react in the presence of O-(7-azabenzotriazol-1-yl)-1,1,3,3-tetramethyl-uroniumhexafluorophosphate (HATU), a tertiary amine such as diisopropylethylamine, in a polar aprotic solvent such as dichloromethane or DMF, at a temperature of between −15° C. and 100° C.

After deprotection of the intermediate using techniques well known to those skilled in the art («Protective Groups in Organic Synthesis», T. W. Greene, John Wiley & Sons, 2006 and «Protecting Groups», P. J. Kocienski, Thieme Verlag, 1994), compound (IV) can be condensed with compound (V) following the methods and techniques described above to lead to compound (VI) after a deprotection step. This compound can then, after condensation with the intermediate (VII) and optional deprotection, lead to the formation of the drug. Compound (VI) can also be coupled with a compound (VII′) in whichR′₃ is a precursor of R₃, in particular an R₃ group protected by a protective group. Coupling followed by deprotection of group R′₃ to lead to R₃ can be carried out following the same procedures as described previously.

Scheme 2 illustrates the second general method which can be used to prepare the drug. In the above general formulas, G is a protective group, R₁, R₂, R₃ and R_(4a) are such as previously defined, and Rob represents -A_(c)-A_(a)H with A_(a) as defined previously and A_(c) representing:

-   -   a (C₁-C₇)alkanediyl group,     -   a         —(CH₂CH₂X₁)_(a1)(CH₂CH₂X₂)_(a2)(CH₂CH₂X₃)_(a3)(CH₂CH₂X₄)_(a4)CH₂*—         group wherein the CH₂ group marked with an asterisk is linked to         the CHO group of R_(4b)CHO,     -   an aryl or heterocycle group,     -   an aryl-(C₁-C₇)alkanediyl or heterocycle-(C₁-C₇)alkanediyl         group, said group being optionally substituted by a (C₁-C₆)alkyl         group, the (C₁-C₇)alkanediyl moiety being linked to the CHO         group of R_(4b)CHO.

At the first step, compound (IX) protected on its amine function by a protective group G is condensed with compound (VI). X may represent a leaving group e.g. a chlorine. In this case, the first step consists of the reaction between an acid chloride and an amine. This reaction can be performed using methods and techniques well known to persons skilled in the art. In one particularly appreciated method the two entities are caused to react in the presence of an organic or inorganic base such as Et₃N, iPr2NEt, pyridine, NaH, Cs₂CO₃, K₂CO₃ in a solvent such as THF, dichloromethane, DMF, DMSO at a temperature notably between −20° and 100° C. X may also represent a hydroxyl. In this case, the first step is a condensation reaction between the carboxylic acid (IX) and the amine (VI). This reaction can be conducted following methods and techniques well known to skilled persons. In one particularly appreciated method, the two entities are caused to react in the presence of 1-(3-dimethylaminopropyl)-3-ethyl-carbodiimide (EDC), 3-hydroxy-1,2,3-benzotriazin-4(3H)-one, a tertiary amine such as diisopropylethylamine, in a polar aprotic solvent such as dichloromethane or DMF, at a temperature notably between −15° C. and 40° C. In another particularly appreciated method, these two entities are caused to react in the presence of diethyl phosphorocyanidate (DEPC), a tertiary amine such as triethylamine, in a polar aprotic solvent such as dichloromethane or DMF, at a temperature notably between −15° C. and 40° C.

After deprotection of the intermediate, using techniques well known to skilled persons, the obtained compound (VIII) can lead to the drug after reaction with R₄Y. In this case, Y is a leaving group such as Cl, Br, I, OSO₂CH₃, OSO₂CF₃ or O-Tosyl. The reaction is conducted in the presence of an organic or inorganic base such as Et₃N, iPr₂NEt, NaH, Cs₂CO₃, K₂CO₃, in a polar anhydrous solvent such as dichloromethane, THF, DMF, DMSO at a temperature notably between −20° and 100° C. In another particularly appreciated method, compound (VIII) is caused to react with an aldehyde of formula R_(4b)—CHO where R_(ab) corresponds to a precursor of R₄. In this case, the reaction is a reductive amination in the presence of a reducing agent such as NaBH₄, NaBH₃CN, NaBH(OAc)₃, in a polar solvent such as 1,2-dichloroethane, dichloromethane, THF, DMF, MeOH, in the optional presence of titanium isopropoxide (IV), at a pH which can be controlled by the addition of an acid such as acetic acid at a temperature notably between −20° C. and 100° C.

In the foregoing synthesis schemes, a drug may lead to another drug after an additional reaction step such as saponification for example using methods well known to skilled persons whereby an R₂ group representing an ester (COOMe), is changed to an R₂ group representing a carboxylic acid (COOH).

If it is desired to isolate a drug containing at least one base function in the state of an acid addition salt, this is possible by treating the free base of the drug (containing at least one base function) with a suitable acid, preferably in equivalent quantity. The suitable acid may in particular be trifluoroacetic acid.

III—the Linker (L)

“Linker”, “Linker Unit”, “L” or “link” means, in the present invention, a chemical moiety comprising a covalent bond or a chain of atoms that covalently attaches an antibody to at least one drug.

Linkers may be made using a variety of bifunctional protein coupling agents such as N-succinimidyl-3-(2-pyridyldithio) propionate (SPDP), succinimidyl-4-(N-maleimidomethyl)cyclohexane-1-carboxylate (SMCC), iminothiolane (IT), bifunctional derivatives of imidoesters (such as dimethyl adipimidate HCl), active esters (such as disuccinimidyl suberate), aldehydes (such as glutaraldehyde), bis-azido compounds (such as bis (p-azidobenzoyl) hexanediamine), bis-diazonium derivatives (such as bis-(p-diazoniumbenzoyl)-ethylenediamine), diisocyanates (such as toluene 2,6-diisocyanate), and bis-active fluorine compounds (such as 1,5-difluoro-2,4-dinitrobenzene). Carbon-14-labeled 1-isothiocyanatobenzyl-3-methyldiethylene triaminepentaacetic acid (MX-DTPA) is an exemplary chelating agent for conjugation of cyctotoxic agents to the addressing system. Other cross-linker reagents may be BMPS, EMCS, GMBS, HBVS, LC-SMCC, MBS, MPBH, SBAP, SIA, SIAB, SMCC, SMPB, SMPH, sulfo-EMCS, sulfo-GMBS, sulfo-KMUS, sulfo-MBS, sulfo-SIAB, sulfo-SMCC, and sulfo-SMPB, and SVSB (succinimidyl-(4-vinylsulfone)benzoate) which are commercially available (e.g., from Pierce Biotechnology, Inc., Rockford, Ill., U.S.A).

The linker may be a “non cleavable” or “cleavable”.

In a preferred embodiment, it consists in a “cleavable linker” facilitating release of the drug in the cell. For example, an acid-labile linker, peptidase-sensitive linker, photolabile linker, dimethyl linker or disulfide-containing linker may be used. The linker is, in a preferred embodiment, cleavable under intracellular conditions, such that cleavage of the linker releases the drug from the antibody in the intracellular environment.

For example, in some embodiments, the linker is cleavable by a cleaving agent that is present in the intracellular environment (e.g., within a lysosome or endosome or caveolea). The linker can be, for example, a peptidyl linker that is cleaved by an intracellular peptidase or protease enzyme, including, but not limited to, a lysosomal or endosomal protease. Typically, the peptidyl linker comprises at least two successive amino acids or at least three successive amino acids or is at least two amino acids long or at least three amino acids long. Cleaving agents can include cathepsins B and D and plasmin, all of which are known to hydrolyze dipeptide drug derivatives resulting in the release of active drug inside target cells. For example, a peptidyl linker that is cleavable by the thiol-dependent protease cathepsin-B, which is highly expressed in cancerous tissue, can be used (e.g., a linker comprising or being Phe-Leu or Gly-Phe-Leu-Gly (SEQ ID NO: 53)). In specific embodiments, the peptidyl linker cleavable by an intracellular protease comprises or is Val-Cit or Phe-Lys. One advantage of using intracellular proteolytic release of the drug is that the drug is typically attenuated when conjugated and the serum stabilities of the conjugates are typically high.

In other embodiments, the cleavable linker is pH-sensitive, i.e., sensitive to hydrolysis at certain pH values. Typically, the pH-sensitive linker is hydrolyzable under acidic conditions. For example, an acid-labile linker that is hydrolyzable in the lysosome (e.g., a hydrazone, semicarbazone, thiosemicarbazone, cis-aconitic amide, orthoester, acetal, ketal, or the like) can be used. Such linkers are relatively stable under neutral pH conditions, such as those in the blood, but are unstable at below pH 5.5 or 5.0, the approximate pH of the lysosome. In certain embodiments, the hydrolyzable linker is a thioether linker (such as, e.g., a thioether attached to the drug via an acylhydrazone bond).

In yet other embodiments, the linker is cleavable under reducing conditions (e.g., a disulfide linker). A variety of disulfide linkers are known in the art, including, for example, those that can be formed using SATA (N-succinimidyl-S-acetylthioacetate), SPDP (N-succinimidyl-3-(2-pyridyldithio)propionate), SPDB (N-succinimidyl-3-(2-pyridyldithio)butyrate) and SMPT (N-succinimidyl-oxycarbonyl-alpha-methyl-alpha-(2-pyridyl-dithio)toluene).

In certain preferred embodiments, the linker unit may have the following general formula: -(T)_(a)-(W)_(w)-(Y)_(y)

wherein:

T is a stretcher unit;

a is 0 or 1;

W is an amino acid unit;

w is an integer ranging from 0 to 12;

Y is a spacer unit;

y is 0, 1 or 2.

The stretcher unit (T), when present, links the antibody to an amino acid unit (W) when present, or to the spacer unit when present, or directly to the drug. Useful functional groups that can be present on the antibody, either naturally or via chemical manipulation, include sulfhydryl, amino, hydroxyl, the anomeric hydroxyl group of a carbohydrate, and carboxyl. Suitable functional groups are sulfhydryl and amino Sulfhydryl groups can be generated by reduction of the intramolecular disulfide bonds of the antibody, if present. Alternatively, sulfhydryl groups can be generated by reaction of an amino group of a lysine moiety of the antibody with 2-iminothiolane or other sulfhydryl generating reagents. In specific embodiments, the antibody is engineered to carry one or more lysines. More preferably, the antibody can be engineered to carry one or more Cysteines (cf. THIOMAB).

In certain specific embodiments, the stretcher unit forms a bond with a sulfur atom of the antibody. The sulfur atom can be derived from a sulfhydryl (—SH) group of a reduced antibody.

In certain other specific embodiments, the stretcher unit is linked to the antibody via a disulfide bond between a sulfur atom of the antibody and a sulfur atom of the stretcher unit.

In other specific embodiments, the reactive group of the stretcher contains a reactive site that can be reactive to an amino group of the antibody. The amino group can be that of an arginine or a lysine. Suitable amine reactive sites include, but are not limited to, activated esters (such as succinimide esters, 4-nitrophenyl esters, pentafluorophenyl esters), anhydrides, acid chlorides, sulfonyl chlorides, isocyanates and isothiocyanates.

In yet another aspect, the reactive function of the stretcher contains a reactive site that is reactive to a modified carbohydrate group that can be present on the antibody. In a specific embodiment, the antibody is glycosylated enzymatically to provide a carbohydrate moiety or is naturally glycosylated. The carbohydrate may be mildly oxidized with a reagent such as sodium periodate and the resulting carbonyl unit of the oxidized carbohydrate can be condensed with a stretcher that contains a functionality such as a hydrazide, an oxime, a reactive amine, a hydrazine, a thiosemicarbazide, a hydrazine carboxylate, or an arylhydrazide.

According to a particular embodiment, the stretcher unit has the following formula:

wherein

L₂ is (C₄-C₁₀)cycloalkyl-carbonyl, (C₂-C₆)alkyl or (C₂-C₆)alkyl-carbonyl (the cycloalkyl or alkyl moieties being linked to the nitrogen atom of the maleimide moiety),

the asterisk indicates the point of attachment to the amino acid unit, if present, to the spacer unit, if present, or to the drug D, and

the wavy line indicates the point of attachment to the antibody A_(b).

By “(C₄-C₁₀)cycloalkyl” in the present invention is meant a hydrocarbon cycle having 4 to 10 carbon atoms including, but not limited to, cyclopentyl, cyclohexyl and the like.

L₂ can be advantageously (C₂-C₆)alkyl-carbonyl such as a pentyl-carbonyl of the following formula:

wherein

the asterisk indicates the point of attachment to the amino acid unit, if present, to the spacer unit, if present, or to the drug D; and

the wavy line indicates the point of attachment to the nitrogen atom of the maleimide moiety.

The amino acid unit (W), when present, links the stretcher unit (T) if present, or otherwise the antibody to the spacer unit (Y) if the spacer unit is present, or to the drug if the spacer unit is absent.

As above mentioned, (W)_(w) is absent (w=0) or may be a dipeptide, tripeptide, tetrapeptide, pentapeptide, hexapeptide, heptapeptide, octapeptide, nonapeptide, decapeptide, undecapeptide or dodecapeptide unit, wherein the amino acids forming the peptides can be different from one another.

Thus (W)_(w) can be represented by the following formula: (W1)_(w1)(W2)_(w2)(W3)_(w3)(W4)_(w4)(W5)_(w5), wherein each W1 to W5 represents, independently from one another, an amino acid unit and each w1 to w5 is 0 or 1.

In some embodiments, the amino acid unit (W)_(w) may comprise amino acid residues such as those occurring naturally, as well as minor amino acids and non-naturally occurring amino acid analogs, such as citrulline.

The amino acid residues of the amino acid unit (W)_(w) include, without limitation, alanine, valine, leucine, isoleucine, methionine, phenylalanine, tryptophan, proline, lysine protected or not with acetyl or formyl, arginine, arginine protected or not with tosyl or nitro groups, histidine, ornithine, ornithine protected with acetyl or formyl, and citrulline. Exemplary amino acid linker components include preferably a dipeptide, a tripeptide, a tetrapeptide or a pentapeptide, notably a dipeptide or a tripeptide.

Exemplary dipeptides include: Val-Cit, Ala-Val, Ala-Ala, Val-Ala, Lys-Lys, Cit-Cit, Val-Lys, Ala-Phe, Phe-Lys, Ala-Lys, Phe-Cit, Leu-Cit, Ile-Cit, Trp-Cit, Phe-Ala, Phe-N⁹-tosyl-Arg, Phe-N⁹-Nitro-Arg.

Exemplary tripeptides include: Val-Ala-Val, Ala-Asn-Val, Val-Leu-Lys, Ala-Ala-Asn, Phe-Phe-Lys, Gly-Gly-Gly, D-Phe-Phe-Lys, Gly-Phe-Lys.

Exemplary tetrapeptide include: Gly-Phe-Leu-Gly (SEQ ID NO: 53), Ala-Leu-Ala-Leu (SEQ ID NO. 54).

Exemplary pentapeptide include: Pro-Val-Gly-Val-Val (SEQ ID NO: 55).

According to a particular embodiment, (W)_(w) can be a dipeptide (i.e. w=2) such as Val-Cit, or the linker lacks an amino acid unit (w=0). When the linker lacks an amino acid unit, preferably it lacks also a spacer unit.

According to a preferred embodiment, w=0 (i.e. (W)_(w) is a single bond) or w=2 (i.e. (W)_(w) is a dipeptide) and (W)_(w) can thus be selected from:

and in particular is Val-Cit,

wherein

the asterisk indicates the point of attachment to the spacer unit if present, or to the drug D; and

the wavy line indicates the point of attachment to L₂.

Amino acid linker components can be designed and optimized in their selectivity for enzymatic cleavage by a particular enzyme, for example, a tumor-associated protease, cathepsin B, C and D, or a plasmin protease.

The amino acid unit of the linker can be enzymatically cleaved by an enzyme including, but not limited to, a tumor-associated protease to liberate the drug.

The amino acid unit can be designed and optimized in its selectivity for enzymatic cleavage by a particular tumor-associated protease. The suitable units are those whose cleavage is catalyzed by the proteases, cathepsin B, C and D, and plasmin.

The spacer unit (Y), when present, links an amino acid unit if present, or the stretcher unit if present, or otherwise the antibody to the drug. Spacer units are of two general types: self-immolative and non self-immolative. A non self-immolative spacer unit is one in which part or all of the spacer unit remains bound to the drug after enzymatic cleavage of an amino acid unit from the antibody-drug conjugate. Examples of a non self-immolative spacer unit include, but are not limited to a (glycine-glycine) spacer unit and a glycine spacer unit. To liberate the drug, an independent hydrolysis reaction should take place within the target cell to cleave the glycine-drug unit bond.

In a particular embodiment, a non self-immolative the spacer unit (Y) is Gly.

Alternatively, an antibody-drug conjugate containing a self-immolative spacer unit can release the drug without the need for a separate hydrolysis step. In these embodiments, (Y) is a residue of p-aminobenzyl alcohol (PAB) unit that is linked to (W)_(w) via the nitrogen atom of the PAB group, and connected directly to the drug via a ester, carbonate, carbamate or ether group.

Other examples of self-immolative spacers include, but are not limited to, aromatic compounds that are electronically equivalent to the PAB group such as residues of 2-aminoimidazol-5-methanol derivatives and ortho or para-aminobenzylacetals. Spacers can be used that undergo facile cyclization upon amide bond hydrolysis, such as substituted and unsubstituted 4-aminobutyric acid amides, appropriately substituted bicyclo[2.2.1] and bicyclo[2.2.2] ring systems and 2-aminophenylpropionic acid amides.

In an alternate embodiment, the spacer unit is a branched bis(hydroxymethyl)styrene (BHMS) unit, which can be used to incorporate additional drugs.

In a particular embodiment, the spacer unit (Y) is PAB-carbonyl with PAB being

(the oxygen of the PAB unit being linked to the carbonyl), and y=1 or the linker lacks a spacer unit (y=0).

In a particular embodiment, the linker has the following formula (III):

wherein

L₂ is (C₄-C₁₀)cycloalkyl-carbonyl, (C₂-C₆)alkyl or (C₂-C₆)alkyl-carbonyl (the carbonyl of these moieties, when present, being linked to (W)_(w)),

W represents an amino acid unit, with w representing an integer comprised between 0 and 5,

Y is PAB-carbonyl, with PAB being

(the oxygen of the PAB unit being linked to the carbonyl), and y is 0 or 1 (preferably y is 0 when w is 0 and y is 0 or 1 when w is comprised between 1 and 5),

the asterisk indicates the point of attachment to the drug D, and

the wavy line indicates the point of attachment to the antibody A_(b).

Advantageously, L₂ is (C₂-C₆)alkyl-carbonyl such as a pentyl-carbonyl of the following formula:

wherein

the asterisk indicates the point of attachment to (W)_(w); and

the wavy line indicates the point of attachment to the nitrogen atom of the maleimide moiety.

According to a preferred embodiment, the linker L is selected from:

wherein the asterisk indicates the point of attachment to the drug D, and the wavy line indicates the point of attachment to the antibody A_(b).

IV—The Antibody-Drug-Conjugate (ADC)

In a preferred embodiment, the antibody-drug conjugate of the invention may be prepared by any method known by the person skilled in the art such as, without limitation, i) reaction of a nucleophilic group of the antibody with a bivalent linker reagent followed by reaction with a nucleophilic group of the drug or ii) reaction of a nucleophilic group of the drug with a bivalent linker reagent followed by reaction with a nucleophilic group of the antibody.

Nucleophilic groups on antibody include, without limitation, N-terminal amine groups, side chain amine groups (e.g. lysine), side chain thiol groups, and sugar hydroxyl or amino groups when the antibody is glycosylated.

Nucleophilic groups on the drug include, without limitation, amine, thiol, and hydroxyl groups, and preferably amine groups.

Amine, thiol, and hydroxyl groups are nucleophilic and capable of reacting to form covalent bonds with electrophilic groups on linker moieties and linker reagents including, without limitation, active esters such as NHS esters, HOBt esters, haloformates, and acid halides; alkyl and benzyl halides such as haloacetamides; aldehydes; ketones; carboxyl; and maleimide groups. The antibody may have reducible interchain disulfides, i.e. cysteine bridges. The antibody may be made reactive for conjugation with linker reagents by treatment with a reducing agent such as DTT (dithiothreitol). Each cysteine bridge will thus form, theoretically, two reactive thiol nucleophiles. Additional nucleophilic groups can be introduced into the antibody through any reaction known by the person skilled in the art. As non limitative example, reactive thiol groups may be introduced into the antibody by introducing one or more cysteine residues.

Antibody-drug conjugates may also be produced by modification of the antibody to introduce electrophilic moieties, which can react with nucleophilic substituents on the linker reagent. The sugars of glycosylated antibody may be oxidized to form aldehyde or ketone groups which may react with the amine group of linker reagents or drug. The resulting imine Schiff base groups may form a stable linkage, or may be reduced to form stable amine linkages. In one embodiment, reaction of the carbohydrate portion of a glycosylated antibody with either galactose oxidase or sodium meta-periodate may yield carbonyl (aldehyde and ketone) groups in the protein that can react with appropriate groups on the drug. In another embodiment, proteins containing N-terminal serine or threonine residues can react with sodium meta-periodate, resulting in production of an aldehyde in place of the first amino acid.

In a preferred embodiment, the antibody-drug conjugate of the invention is prepared by preparation of the drug-linker moiety followed by coupling between a nucleophilic group of the antibody (for ex. the SH group of a cysteine moiety) and an electrophilic group of the drug-linker moiety (for ex. a maleimide).

1. Drug-Linker

The Drug-Linker moiety can be prepared by coupling:

-   -   the linker with the drug,     -   a part of the linker with the drug before completing the         synthesis of the linker,     -   the linker with a part or a precursor of the drug before         completing the synthesis of the drug, or     -   a part of the linker with a part or a precursor of the drug         before completing the synthesis of the linker and the drug.

The coupling reactions are well known reactions for the one skilled in the art between a nucleopilic group and an electrophilic group.

The nucleophilic group can be in particular an amine, thiol or hydroxyl group, and notably an amine or hydroxyl group. In a preferred embodiment it is a primary or secondary amine group.

The electrophilic group can be a carboxylic acid group (COOH) optionally in an activated form or an activated carbonate ester moiety.

By “activated form” of a carboxylic acid is meant a carboxylic acid in which the OH moiety of the COOH function has been replaced with an activated leaving group (LG) enabling coupling of the activated carboxylic acid group with an amino group in order to form an amide bond and release the compound LG-H. Activated forms may be activated esters, activated amides, anhydrides or acyl halides such as acyl chlorides. Activated esters include derivatives formed by reaction of the carboxylic acid group with N-hydroxybenzotriazole or N-hydroxysuccinimide.

By “activated carbonate ester” is meant a carbonate ester comprising a —OC(O)OR moiety in which OR represents a good leaving group enabling coupling of the activated carbonate ester with an amino group in order to form a carbamate moiety and release the compound ROH. The R group of the activated carbonate ester includes, without limitation, the p-nitro-phenyl, pentafluorophenyl, 2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl and benzyl groups, preferably the p-nitro-phenyl and pentafluorophenyl groups.

When the linker has the following formula (III):

the Drug-Linker moiety has the following formula (IV):

and the last step of the synthesis of the Drug-Linker moiety is generally the coupling between a compound of the following formula (V):

where L₂ is as defined previously and LG represents a leaving group notably a halide such as a chloride or a group derived from N-hydroxysuccinimide, and a compound of the following formula (VI): H-(W)_(w)-(Y)_(y)-D  (VI).

When y=1 and Y=PAB-carbonyl, the compound of formula (VI) can be prepared by the coupling between the drug (DH) and a compound of the following formula (VII) or a protected form thereof: H-(W)_(w)-PAB-CO-OR  (VII) where W and w are as defined previously and R is as defined in the definition of the “activated carbonate ester”.

When the compound of formula (VII) is in a protected form, final step of deprotection is necessary.

When y=0, the compound (VI) has the formula H—(W)_(w)-D, wherein (W)_(w) and D are composed of amino acid units. Consequently, the compound (VI) can be prepared in this case by a conventional peptide synthesis method well known to the one skilled in the art.

2. A_(b)-Linker-Drug

A preferred embodiment according to the invention consists of a coupling between a cysteine present on the antibody and an electrophilic group of the Drug-Linker moiety, preferably with a maleimide moiety present on the Drug-Linker moiety.

The maleimide-cysteine coupling can be performed by methods well known to the person skilled in the art.

Generally, antibodies do not contain many, if any, free and reactive cysteine thiol groups which can be linked to a drug moiety. Most cysteine thiol residues in antibodies exist as disulfide bridges and must be reduced with a reducing agent such as dithiothreitol (DTT) or TCEP, under partial or total reducing conditions. The loading (drug/antibody ratio) of an ADC may be controlled in several different manners, including: (i) limiting the molar excess of drug-linker intermediate (D-L) or linker reagent relative to antibody, (ii) limiting the conjugation reaction time or temperature, and (iii) partial or limited reducing conditions for cysteine thiol modification.

The disulfide bond structure of human IgGs is now well established (reviewed in Liu and May, mAbs 4 (2012): 17-23). There are in fact many similarities and some differences with regard to the disulfide bond structures of the 4 human IgG subclasses, namely IgG1, IgG2, IgG3 and IgG4. All IgG subclasses contain invariably 12 intra-chain disulfide bridges and the differences reside in their inter-chain disulfide bonds formed between heavy and light chains. Each intra-chain disulfide bond is associated with an individual IgG domain, i.e. variable (VL and VH) and constant (CL, CH1, CH2 and CH3) domains. The 2 heavy chains are linked in their hinge region by a variable number of disulfide bridges: 2 for IgG1 and IgG4, 4 for IgG2 and 11 for IgG3. The heavy and light chains of the IgG1 are connected by a disulfide bond between the last cysteine residue of the light chain and the fifth residue of the heavy chain, whereas for the other subclasses, IgG2, IgG3 and IgG4, the light chain is linked to the heavy chain by a disulfide bond between the last cysteine residue of the light chain and the third cysteine residue of the heavy chain, which is located at the interface of VH and CH1 domains. Disulfide bond structures other than these classical structures have been described for IgG2 and IgG4 (reviewed in Liu and May, mAbs 4 (2012): 17-23). Inter-chain disulfide bonds are highly solvent exposed and are consequently much more reactive than the intra-chain disulfide bonds, which are buried in anti-parallel beta-sheet structures within each domain and are not solvent exposed. For these reasons, whatever the antibody isotype, coupling will take place on inter-chain exposed cysteine residues after mild reduction. Each inter-chain disulfide bridge can thus form, theoretically, two sites of conjugation.

Additional nucleophilic groups can be introduced into antibodies through the reaction of lysines with 2-iminothiolane (Traut's reagent) resulting in the conversion of an amine into a thiol. Reactive thiol groups may also be introduced into the antibody (or fragment thereof) by engineering one, two, three, four, or more cysteine residues (e.g., preparing mutant antibodies comprising one or more non-native cysteine amino acid residues). U.S. Pat. No. 7,521,541 teaches engineering antibodies by introduction of reactive cysteine amino acids.

Cysteine amino acids may be engineered at reactive sites in an antibody and which do not form intrachain or intermolecular disulfide linkages (Junutula, et al., 2008b Nature Biotech., 26(8):925-932; Dornan et al (2009) Blood 114(13):2721-2729; U.S. Pat. Nos. 7,521,541; 7,723,485; WO2009/052249). The engineered cysteine thiols may react with linker reagents or the drug-linker reagents of the present invention which have thiol-reactive, electrophilic groups such as maleimide or alpha-halo amides to form ADC with cysteine engineered antibodies and the drug moieties. The location of the drug moiety can thus be designed, controlled, and known. The drug loading can be controlled since the engineered cysteine thiol groups typically react with thiol-reactive linker reagents or drug-linker reagents in high yield. Engineering an IgG antibody to introduce a cysteine amino acid by substitution at a single site on the heavy or light chain gives two new cysteines on the symmetrical antibody. A drug loading near 2 can be achieved with near homogeneity of the conjugation product ADC.

Where more than one nucleophilic or electrophilic group of the antibody reacts with a drug-linker intermediate, or linker reagent followed by drug moiety reagent, then the resulting product is a mixture of ADC compounds with a distribution of drug moieties attached to an antibody, e.g. 1, 2, 3, etc. Liquid chromatography methods such as polymeric reverse phase (PLRP) and hydrophobic interaction (HIC) may separate compounds in the mixture by drug loading value. Preparations of ADC with a single drug loading value (p) may be isolated, however, these single loading value ADCs may still be heterogeneous mixtures because the drug moieties may be attached, via the linker, at different sites on the antibody.

For some antibody-drug conjugates, drug ratio may be limited by the number of attachment sites on the antibody. High drug loading, e.g. drug ratio >5, may cause aggregation, insolubility, toxicity, or loss of cellular permeability of certain antibody-drug conjugates. Typically, less drug moieties than the theoretical maximum are conjugated to an antibody during a conjugation reaction.

The drug loading also referred as the Drug-Antibody ratio (DAR) is the average number of drugs per cell binding agent.

In the case of antibody IgG1 and IgG4 isotypes, where the drugs are bound to cysteines after partial antibody reduction, drug loading may range from 1 to 8 drugs (D) per antibody, i.e. where 1, 2, 3, 4, 5, 6, 7, and 8 drug moieties are covalently attached to the antibody.

In the case of an antibody IgG2 isotype, where the drugs are bound to cysteines after partial antibody reduction, drug loading may range from 1 to 12 drugs (D) per antibody, i.e. where 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 drug moieties are covalently attached to the antibody.

Compositions of ADC include collections of cell binding agents, e.g. antibodies, conjugated with a range of drugs, from 1 to 8 or 1 to 12.

The average number of drugs per antibody in preparations of ADC from conjugation reactions may be characterized by conventional means such as UV, reverse phase HPLC, HIC, mass spectrometry, ELISA assay, and electrophoresis.

As non limitative embodiment, it is presented herein the conjugation with the IGF-1R antibody c208F2. In this case, the drug is coupled to at least one cysteine selected from i) for the light chain of sequence SEQ ID NO: 28, the residue Cys. in position 214 and ii) for the heavy chain of sequence SEQ ID NO: 23, the residues Cys. in position 223, 229 and 232.

As non limitative embodiment, it is presented herein the conjugation with the IGF-1R antibody c208F2. In this case, the drug is coupled to two, three or four, cysteines selected from i) for the light chain of sequence SEQ ID NO: 28, the residue Cys. in position 214 and ii) for the heavy chain of sequence SEQ ID NO: 23, the residues Cys. in position 223, 229 and 232

As non limitative embodiment, it is presented herein the conjugation with the IGF-1R antibody hz208F2 (var. 1). In this case, the drug is coupled to at least one cysteine selected from i) for the light chain of sequence SEQ ID NO: 39, the residue Cys. in position 214 and ii) for the heavy chain of sequence SEQ ID NO: 37, the residues Cys. in position 223, 229 and 232.

As non limitative embodiment, it is presented herein the conjugation with the IGF-1R antibody hz208F2 (var. 3). In this case, the drug is coupled to two, three or four, cysteines selected from i) for the light chain of sequence SEQ ID NO: 40, the residue Cys. in position 214 and ii) for the heavy chain of sequence SEQ ID NO: 38, the residues Cys. in position 223, 229 and 232.

The same approach could be easily adapted to other antibodies such as, for example, the Ax1 antibodies.

An alternative consists of lysine coupling. An antibody may contain, for example, many lysine residues that do not react with the drug-linker intermediate (D-L) or linker reagent. Only the most reactive lysine groups may react with an amine-reactive linker reagent. Also, only the most reactive cysteine thiol groups may react with a thiol-reactive linker reagent.

Where the compounds of the invention are bound to lysines, drug loading may range from 1 to 80 drugs (D) per cell antibody, although an upper limit of 40, 20, 10 or 8 may be preferred. Compositions of ADC include collections of cell binding agents, e.g. antibodies, conjugated with a range of drugs, from 1 to 80, 1 to 40, 1 to 20, 1 to 10 or 1 to 8.

The ADC of formula (I) according to the invention can be in the form of a pharmaceutically acceptable salt.

In the present invention by “pharmaceutically acceptable” is meant that which can be used in the preparation of a pharmaceutical composition which is generally, safe non-toxic and neither biologically nor otherwise undesirable, and which is acceptable for veterinary use as well as for human pharmaceutical use.

By “pharmaceutically acceptable salt” of a compound is meant a salt which is pharmaceutically acceptable as defined herein and which has the desired pharmacological activity of the parent compound.

Pharmaceutically acceptable salts notably comprise:

(1) the addition salts of a pharmaceutically acceptable acid formed with pharmaceutically acceptable inorganic acids such as hydrochloric, hydrobromic, phosphoric, sulfuric and similar acids; or formed with pharmaceutically acceptable organic acids such as acetic, trifluoroacetic, propionic, succinic, fumaric, malic, tartaric, citric, ascorbic, maleic, glutamic, benzoic, salicylic, toluenesulfonic, methanesulfonic, stearic, lactic and similar acids; and

(2) the addition salts of a pharmaceutically acceptable base formed when an acid proton present in the parent compound is either replaced by a metallic ion e.g. an alkaline metal ion, an alkaline-earth metal ion or an aluminium ion; or coordinated with a pharmaceutically acceptable organic base such as lysine, arginine and similar; or with a pharmaceutically acceptable inorganic base such as sodium hydroxide, potash, calcium hydroxide and similar.

These salts can be prepared from the compounds of the invention containing a base or acid function, and the corresponding acids or bases using conventional chemical methods.

V-Treatment

Finally, the invention relates to an ADC as above described for use as a medicament, in particular in the treatment of cancer.

A further subject of the present invention is a formal (I) compound such as defined above for use as medicinal product, in particular for the treatment of cancer.

The present invention also concerns the use of a formula (I) compound such as defined above for producing a medicinal product, particularly intended for the treatment of cancer.

The present invention also concerns a method for treating cancer comprising the administration to a person in need thereof of an effective mount of a formula (I) compound such as defined above.

Cancers can be preferably selected through Target-related cancers including tumoral cells expressing or over-expressing whole or part of the Target at their surface.

More particularly, said cancers are breast cancer, colon cancer, esophageal carcinoma, hepatocellular cancer, gastric cancer, glioma, lung cancer, melanoma, osteosarcoma, ovarian cancer, prostate cancer, rhabdomyosarcoma, renal cancer, thyroid cancer, uterine endometrial cancer, schwannoma, neuroblastoma, oral squamous cancer, mesothelioma, leiomyosarcoma, Kaposi sarcoma, acute leukemia, colorectal carcinoma, melanoma, pancreatic ductal adenocarcinoma and any drug resistance phenomena or cancers.

For the avoidance of doubt, by drug resistance Target-expressing cancers, it must be understood not only resistant cancers which initially express the Target but also cancers which initially do not express or overexpress the Target but which express the Target once they have become resistant to a previous treatment.

Another object of the invention is a pharmaceutical composition comprising the ADC as described in the specification.

More particularly, the invention relates to a pharmaceutical composition comprising the ADC of the invention with at least an excipient and/or a pharmaceutical acceptable vehicle.

In the present description, the expression “pharmaceutically acceptable vehicle” or “excipient” is intended to indicate a compound or a combination of compounds entering into a pharmaceutical composition not provoking secondary reactions and which allows, for example, facilitation of the administration of the active compound(s), an increase in its lifespan and/or in its efficacy in the body, an increase in its solubility in solution or else an improvement in its conservation. These pharmaceutically acceptable vehicles and excipients are well known and will be adapted by the person skilled in the art as a function of the nature and of the mode of administration of the active compound(s) chosen.

The active ingredient can be administered in unit forms of administration, in a mixture with conventional pharmaceutical carriers, to animals or to human beings. Suitable unit forms of administration comprise forms via oral route and forms for administration via parenteral route (subcutaneous, intradermal, intramuscular or intravenous).

As solid compositions, for oral administration, use can be made of tablets, pills, powders (hard or soft gelatine capsules) or granules. In these compositions, the active ingredient of the invention is mixed with one or more inert diluents such as starch, cellulose, sucrose, lactose or silica, in a stream of argon. These compositions may also comprise substances other than diluents, for example one or more lubricants such as magnesium stearate or talc, a colouring agent, a coating (coated tablets) or a varnish.

The sterile compositions for parenteral administration may preferably be aqueous or non-aqueous solutions, suspensions or emulsions. As solvent or vehicle, use can be made of water, propylene glycol, a polyethylene glycol, vegetable oils, in particular olive oil, injectable organic esters e.g. ethyl oleate or other suitable organic solvents. These compositions may also contain adjuvants, in particular wetting, isotonic, emulsifying, dispersing and stabilising agents. Sterilisation can be performed in several manners, for example by sanitising filtration, by incorporating sterilising agents into the composition, by radiation or by heating. They can also be prepared in the form of solid sterile compositions which can be dissolved at the time of use in sterile water or any other injectable sterile medium.

Preferably, these ADCs will be administered by the systemic route, in particular by the intravenous route, by the intramuscular, intradermal, intraperitoneal or subcutaneous route, or by the oral route. In a more preferred manner, the composition comprising the ADCs according to the invention will be administered several times, in a sequential manner.

The invention concerns thus also a kit comprising at least i) an antibody-drug-conjugate according to the invention and/or a pharmaceutical composition according to the invention and ii) a syringe or vial or ampoule in which the said antibody-drug-conjugate and/or pharmaceutical composition is disposed.

Their modes of administration, dosages and optimum pharmaceutical forms can be determined according to the criteria generally taken into account in the establishment of a treatment adapted to a patient such as, for example, the age or the body weight of the patient, the seriousness of his/her general condition, the tolerance to the treatment and the secondary effects noted.

Other characteristics and advantages of the invention appear in the continuation of the description with the examples and the figures whose legends are represented below.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A, FIG. 1B, and FIG. 1C: Antibody binding to the human native IGF-1R by FACS analyses. FIG. 1A represents the titration curve, on MCF-7 cell line. MFI represents the mean of fluorescent intensity. FIG. 1B represents the EC₅₀ of both murine and chimeric anti-IGF-1R antibodies on the MCF-7 cell line. FIG. 1C represents the B_(max) of chimeric anti-IGF-1R antibodies on MCF-7 cell line.

FIG. 2A and FIG. 2B: Evaluation of hIGF-1R recognition using transfected vs non transfected cells. FIG. 2A Represents titration curves of one chimeric anti-IGF-1R Ab on IGF-1R⁺ cell line. MFI represents the mean of fluorescent intensity. FIG. 2B represents the binding of chimeric anti-IGF-1R Abs on the human IGF-1R⁻ cell line.

FIG. 3A and FIG. 3B: Evaluations of the specificity of Abs to IGF-1R vs hIR using transfected cells. FIG. 3A represents the binding of murine anti-IGF-1R Ab on the hIR transfected cell line. FIG. 3B represents the binding of chimeric anti-IGF-1R Ab on the IR+ cell line. MFI represents the mean of fluorescent intensity. GRO5 anti-hIR Mab (Calbiochem) was introduced as a positive control.

FIG. 4 : Binding of murine anti-IGF-1R Ab on the IM-9 cell line. MFI represents the mean of fluorescent intensity. GRO5 anti-hIR Mab was introduced as a positive control.

FIG. 5A, FIG. 5B, and FIG. 5C: Evaluation of recognition of the monkey IGF-1R. FIG. 5A represents the titration curves of chimeric anti-IGF-1R Ab on the COS-7 cell line. MFI represents the mean of fluorescent intensity. FIG. 5B represents the EC₅₀ of both murine and chimeric anti-IGF-1R antibodies on COS-7 cell line. FIG. 5C represents the EC₅₀ of chimeric anti-IGF-1R antibodies on both NIH 3T3 tansfected cells hIGF1R+ and COS-7 cell lines.

FIG. 6 : Sensorgrams obtained on a SPR technology based BIACORE X₁₀₀ using a CM5 sensorchip activated with more the 11000 RU of mouse anti-Tag His antibody chemically grafted to the carboxymethyl dextran matrix. The experiment was run at a flow rate of 30 μl/min at 25° C. using the HBS-EP+ as the running and samples diluting buffer. The figure showed the superposition of 4 independent sensorgrams aligned on the x-axis at the beginning of the first injection of the analytes and on the y-axis by the baseline defined just before this first injection. The sensorgrams obtained with the capture of the human based sequence of the recombinant soluble IGF1R are marked by diamonds. The sensorgrams obtained with the capture of the cynomolgus based sequence of the recombinant soluble IGF1R are marked by triangles. White symbols correspond to the blank cycles (5 injections of the running buffer) and black symbols correspond to the injections of the growing range of concentrations of c208F2 (5, 10, 20, 40 and 80 nM).

FIG. 7 : Evaluation of the intrinsic effect of anti-hIGF-1R antibodies on the receptor phosphorylation compared to IGF1.

FIG. 8 : Inhibition of IGF-1R phosphorylation in response to IGF-1 by murine anti-hIGF-1R

FIG. 9 : Cell surface signal intensity of anti-IGF-1R antibodies is down-regulated after cell incubation at 37° C. MCF-7 cells were incubated at 4° C. or 37° C. for 4 h with 10 μg/ml of Abs. The figure represents the ΔMFI.

FIG. 10A and FIG. 10B: Antibody surface decay. Cell surface bound antibody was assessed after 10, 20, 30, 60 and 120 min at 37° C. FIG. 10A represents the % of remaining IGF-1R in comparison to the signal intensity measured at 4° C. FIG. 10B represents Half Life calculation usinf Prims Software and using exponential decay fitting.

FIG. 11 : Anti-hIGF-1R Abs are internalized. Cells were incubated with 10 μg/ml of murine Abs for 0, 30 or 60 min at 37° C. cells were permeabilized or not and incubated with a secondary anti-mouse IgG-Alexa 488. Membrane corresponds to the signal intensity w/o permeabilization. Total correspond to the signal intensity after cell permeabilization and cytoplasmic corresponds to internalized A_(b). The name of each evaluated antibody is depicted on the top of each graph.

FIG. 12A and FIG. 12B: Imaging Ab internalization. FIG. 12A: MCF-7 cells incubated with m208F2 for 20 min. at 4° C. and washed before incubation (W) at 37° C. for 15 (X), 30 (Y) and 60 (Z) min. Cells were fixed and permeabilized. The m208F2 Ab was revealed using an anti-mouse IgG Alexa488 and Lamp-1 using a rabbit anti-Lamp-1 antibody and with a secondary anti-rabbit IgG Alexa 555. FIG. 12B: MCF-7 cells were incubated for 30 minutes at 37° C. with anti-hIGF-1R murine antibodies and stained as described above. Colocalization was identified using the colocalization highliter plug-in of the ImageJ software.

FIG. 13 : Involvement of the lysosome pathway in antibody degradation

FIG. 14 : Acidic pH decreases binding capacity of the five murine anti-IGF-1R antibodies.

FIG. 15A, FIG. 15B, FIG. 15C, and FIG. 15D: Binding characteristic of the first humanized form of the c208F2 Mab. Binding properties of the hz208F2 VH3/VL3 mAb was evaluated on the human cell line MCF-7 (A), on the monkey cell line COS-7 (B) and on the transfected murine cell line expressing the human insulin receptor (C). The binding of both the murine and the chimeric 208F2 mAbs was evaluated in parallel. The anti-hIR antibody clone GRO5 was used to verify the expression of the hIR on the transefected cell line (D).

FIG. 16 : hz208F2 VH3/VL3 antibody surface decay

FIG. 17 : Superposition of to sensorgrammes obtained with a SPR based BIACORE X100 device at a temperature of 25° C. with a CM5 sensor chip activated on both flowcells with around 12.000 RU of a mouse anti-TagHis monoclonal antibodies chemically grafted to the carboxymethyldextran matrix using a HBS-EP+ as the running buffer at a flow rate of 30 μl/min. Each sensorgrammes (the first one marked by triangles and the second one marked by diamonds) correspond to a complete cycle:

-   -   1—Injection during one minute of a solution of recombinant         h-IGF1R (10 μg/ml) on the second flowcell.     -   2—For the first sensorgramme 5 injections of running buffer         during 90 s each     -   For the second sensorgramme five injections in the growing range         of concentrations of the anti-IGF1R c208F2 antibody solutions         during 90 s each.     -   3—A delay of 300 s for the determination of the dissociation         kinetic rates.     -   4—A regeneration of the surface by an injection during 45 s of a         10 mM Glycine, HCl pH 1.5 buffer.

FIG. 18 : The sensorgramme corresponding to the subtraction of the blank sensorgramme (5 injections of HBS-EP+) to the sensorgramme obtained with the growing range of concentrations of the anti-IGF1R c208F2 solutions is presented in grey. The theoretical sensorgramme corresponding to the 1:1 model with the following parameters: k_(on)=(1.206±0.036)×10⁶ M⁻¹.s⁻¹, k_(off)=(7.81±0.18)×10⁻⁵ s⁻¹, Rmax=307.6±0.3 RU is presented by a thin black line. The calculated concentrations of c208F2 are reported on the graph: only the highest concentration (24 nM) is considered as a constant).

FIG. 19 : The dissociation constants correspond to the mean of the four experiments run for each antibody and correspond to the ratio: k_(off)/k_(on)×10¹² to be express in the pM unit. The error bars correspond to the standard error (n=4).

FIG. 20 : The half-lives correspond to the mean of the four experiments run for each antibody and correspond to the ratio:Ln(2)/k_(off)/3600 to be express in the h unit. The error bars correspond to the standard error (n=4).

FIG. 21 : Cell cytotoxicity of anti-IGF-1R coupled with three different compounds. Five chimeric antibodies anti-IGF-1R were coupled with either E-13, G-13 or F-63. An irrelevant antibody c9G4 was also coupled with the same compounds.

FIG. 22A, FIG. 22B, and FIG. 22C: in vivo evaluation of c208F2-E-13 (FIG. 22A), c208F2-G-13 (FIG. 22B) and c208F2-F-63 (FIG. 22C) in the MCF-7 xenograft model.

FIG. 23A and FIG. 23B: in vivo evaluation of both c208F2-E-13 (FIG. 23A) and c208F2-G-13 (FIG. 23B) compared to ADCs control (c9G4-E13 and c9G4-G-13) in the MCF-7 xenograft model.

FIG. 24A, FIG. 24B, and FIG. 24C: Binding specificity of 1613F12 on the immobilized rhAx1-Fc protein (24A), rhDtk-Fc (24B) or rhMer-Fc (24C) proteins by ELISA.

FIG. 25 : FACS analysis of the 1613F12 binding on human tumor cells

FIG. 26 : ELISA experiments studying binding on rhAx1-Fc protein of both m1613F12 and hz1613F12.

FIG. 27A, FIG. 27B, and FIG. 27C Immunofluorescence microscopy of SN12C cells after incubation with 1613F12 FIG. 27A—Photographs of the mIgG1 isotype control conditions both for the membrane and the intracellular staining. FIG. 27B-Membrane staining. FIG. 27C—Intracellular staining of both Ax1 receptor using 1613F12 and of the early endosome marker EEA1. Image overlays are presented bellow and co-localizations visualized are indicated by the arrows.

FIG. 28A and FIG. 28B: FIG. 28A represents the cytotoxic activity of the hz1613F12-E-13 on both SN12c (Ax1⁺) and MCF-7 (Ax1⁻) cell lines. FIG. 28B represents the cytotoxic activity of the hz1613F12-G-13 on both SN12c (Ax1⁺) and MCF-7 (Ax1⁻) cell lines.

FIG. 29A and FIG. 29B: In vivo activity of the trastuzumab antibody conjugated to either E-13 (29A) or G-13 (29B) compounds in the Calu-3 xenograft model.

FIG. 30A, FIG. 30B, and FIG. 30C: In vivo activity of the trastuzumab antibody conjugated to either E-13 (FIG. 30A) or G-13 (FIG. 30B) compounds or alone (FIG. 30C) in the JIMT-1 xenograft model.

EXAMPLES Example 1: Generation of Murine Antibodies Raised Against IGF-1R ECD

To generate murine monoclonal antibodies (Mabs) against human extracellular domain (ECD) of the human IGF-1 receptor (hIGF1R), 5 BALB/c mice were immunized 3-times s.c. with 10 μg of the rhIGF-1R protein (R&D Systems, Cat No. 391-GR). As an alternative, three additional immunizations with 10 μg of the murine extracellular domain (ECD) of IGF-1R (R&D Systems, Cat No. 6630-GR/Fc) were performed on some animals. The first immunization was done in presence of Complete Freund Adjuvant (Sigma, St Louis, Md., USA). Incomplete Freund adjuvant (Sigma) was added for following immunizations. Three days prior to the fusion, immunized mice were boosted with 10 μg of the rhIGF-1R protein. Then splenocytes and lymphocytes were prepared by perfusion of the spleen and by mincing of the proximal lymph nodes, respectively, harvested from 1 out of the 5 immunized mice (selected after sera titration of all mice) and fused to SP2/0-Ag14 myeloma cells (ATCC, Rockville, Md., USA). The fusion protocol is described by Kohler and Milstein (Nature, 256:495-497, 1975). Fused cells are then subjected to HAT selection. In general, for the preparation of monoclonal antibodies or their functional fragments, especially of murine origin, it is possible to refer to techniques which are described in particular in the manual “Antibodies” (Harlow and Lane, Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor N.Y., pp. 726, 1988). Approximately 10 days after the fusion, colonies of hybrid cells were screened. For the primary screen, supernatants of hybridomas were evaluated for the secretion of Mabs raised against the IGF-1R ECD protein by FACS analysis using human breast MCF7 tumor cells (ATCC) and/or monkey COS7 cells (African green monkey kidney-S V40 transformed) which express monkey IGF-1R on their cell surface. More precisely, for the selection by flow cytometry, 10⁵ cells (either MCF7 or COS7) were plated in each well of a 96 well-plate in PBS containing 1% BSA and 0.01% sodium azide (FACS buffer) at 4° C. After a 2 min centrifugation at 2000 rpm, the buffer was removed and hybridoma supernatants to be tested were added. After 20 min of incubation at 4° C., cells were washed twice and an Alexa 488-conjugated goat anti-mouse antibody 1/500° diluted in FACS buffer (#A11017, Molecular Probes Inc., Eugene, USA) was added and incubated for 20 min at 4° C. After a final wash with FACS buffer, cells were analyzed by FACS (Facscalibur, Becton-Dickinson) after addition of propidium iodide to each tube at a final concentration of 40 μg/ml. Wells containing cells alone and cells incubated with the secondary Alexa 488-conjugated antibody were included as negative controls. Isotype controls were used in each experiment (Sigma, ref M90351MG). At least 5000 cells were assessed to calculate the mean value of fluorescence intensity (MFI).

Additionally an internalization assay was performed in order to select only internalizing antibodies. For this assay, MCF7 tumor cell line was cultured in RMPI 1640 without phenol red with 1% L-glutamine and 10% of FACS for 3 days before experiment. Cells were then detached using trypsin and 100 μl of a cell suspension at 4.10⁵ cell/ml are plated in 96-multiwell plates in RPMI1640 without phenol red with 1% L-glutamine and 5% FBS. After a 2 min centrifugation at 2000 rpm, cells were resupended in 50 μl of either hybridoma supernatants or control antibody solutions (positive and isotype controls at 1 μg/ml). After a 20 min incubation time at 4° C., cells were centrifuged 2 min at 2000 rpm and resuspended in either cold (4° C.) or warm (37° C.) complete culture medium. Cells were then incubated for 2 hours either at 37° C. or at 4° C. Then cells were washed three times with FACS buffer. An Alexa 488-labeled goat anti-mouse IgG antibody was incubated for 20 minutes and cells were washed three times before FACS analysis on propidium iodide negative cell population.

Following the FACS analysis, two parameters were determined: (i) the difference of the fluorescent signal detected on the surface of cells incubated at 4° C. with those obtained with the cells incubated at 37° C. with one hybridoma supernatant and (ii) the percentage of remaining IGF1R on the cell surface.

The percentage of remaining hIGF 1R is calculated as follows: % remaining IGF-1R=(MFI_(Ab 37° C.)/MFI_(Ab 4° C.))×100.

In addition three ELISAs were performed (either before or after cloning) to study the binding of antibodies on the recombinant human (hIGF-1R) and murine (mIGF-1R) proteins, and on the recombinant human Insulin Receptor (hIR) protein. Hybridoma secreting antibody showing binding on rh- and/or rm-IGF-1R and no binding on rhIR were retained. Briefly, 96-well ELISA plates (Costar 3690, Corning, N.Y., USA) were coated 100 μl/well of either the rhIGF-1R protein (R&D Systems, cat No. 391-GR) at 0.6 μg/ml or rmIGF-1R protein (R&D Systems, cat No. 6630-GR/Fc) at 1 μg/ml or rhIR protein (R&D Systems, cat No. 1544-IR/CF) at 1 μg/ml in PBS overnight at 4° C. The plates were then blocked with PBS containing 0.5% gelatin (#22151, Serva Electrophoresis GmbH, Heidelberg, Germany) for 2 h at 37° C. Once the saturation buffer discarded by flicking plates, 100 μl of each supernatant dilution were added to each well (either undiluted hybridoma supernatant either supernatant serial dilutions) and incubated for 1 h at 37° C. After three washes, 100 μl horseradish peroxidase-conjugated polyclonal goat anti-mouse IgG (#115-035-164, Jackson Immuno-Research Laboratories, Inc., West Grove, Pa., USA) was added at a 1/5000 dilution in PBS containing 0.1% gelatin and 0.05% Tween 20 (w:w) for 1 h at 37° C. Then, ELISA plates were washed 3-times and the TMB (#UP664782, Uptima, Interchim, France) substrate is added. After a 10 min incubation time at room temperature, the reaction was stopped using 1 M sulfuric acid and the optical density at 450 nm is measured.

Hybridoma secreting antibody of interest were expanded and cloned by limit dilution. Once isotyped, one clone of each code was expanded and frozen. Each antibody of interest was produced in in vitro production systems named CellLine (Integra Biosciences) for further characterization.

Additional assays to address binding specificity FACS analyses were performed on IM9 cells (human IR expressing B lymphoblasts) as well as on hIGF-1R transfected cells versus non transfected cells.

All the data corresponding to the selected antibodies were summarized in Table 9 and demonstrated that the five selected antibodies strongly recognize the native human IGF-1R expressed either on MCF-7 breast cancer cells or on transfected cells. They also recognize monkey IGF-1R on COS-7 cells. These antibodies do not cross react with the human insulin receptor highly expressed on IM9 cells. It has to be noticed that these antibodies poorly recognize the rhIGF-1R ECD protein when directly coated to ELISA plates.

TABLE 9 ELISA (SNT at MCF7 Internalisation Assay FACS (SNT at 5 μg/ml) 5 μg/ml) (SNT at 5 μg/ml) MFI D.O 450 nm % Δ IM9 Cos-7 non Tf hybridoma rh rm rh MFI remaining (MFI 4° C.- (h (monkey cells name Isotype CNCM IGF-1R IGF-1R Insulin R 4° C. 37° C. rh IGF1R MFI 37° C.) IR*) IGF1R*) Tf hIGF1R* (h IGF1r*) 208F2 IgG1 K I-4757 0.163 0.099 0.140 355 94 27 261 4 106 2197 22 212A11 IgG1 K I-4773 0.232 0.102 0.141 390 106 27 284 7 125 2187 23 213B10 IgG1 K I-4774 0.399 0.127 0.110 386 115 30 271 7 122 2055 23 214F8 IgG1 K I-4775 0.349 0.102 0.115 386 111 29 275 7 132 2137 20 219D6 IgG1 K I-4736 0.329 0.112 0.106 349 106 30 243 7 114 2110 21

Example 2: Antibody Binding to the Human Native IGF-1R by FACS Analyses

The five murine IGF-1R antibodies were chimerized. The binding properties of both the murine and the chimeric IGF-1R antibodies were evaluated by FACS analyses on the human MCF-7 breast adenocarcinoma cell line (ATCC #HTB-22) using increasing antibody concentrations. For that purpose, cells (1×10⁶ cells/ml) were incubated with IGF-1R antibodies for 20 min. at 4° C. in FACS buffer (PBS, 0.1% BSA, 0.01% NaN₃). They were then washed 3 times and incubated with the appropriate secondary antibody coupled with Alexa 488 for 20 additional minutes at 4° C. in the dark before being washed 3 times in FACS buffer. The binding of anti-IGF-1R antibodies was immediately performed on viable cells which were identified using propidium iodide (that stains dead cells). The maximum of signal intensity obtained with each antibody was designed as B_(max) and expressed in mean of fluorescence intensity (MFI). The EC₅₀ of binding expressed in molarity (M) was calculated using a nonlinear regression analysis (GraphPad Prims 4.0).

The titration curve of each murine or chimeric Ab demonstrated that all generated antibodies are capable to recognize the native IGF-1R form with a typical saturation profile (FIG. 1A). In order to rank antibodies and to compare the binding properties of both murine and chimeric Abs, the binding EC₅₀ of each compound was determined using a non linear regression analysis. The comparison of the EC₅₀ of each murine Ab with its corresponding chimeric form showed that the 2 forms displayed the same binding properties demonstrating that the Ab chimerization did not affect IGF-1R recognition (FIG. 1B-C). EC₅₀ and B_(max) values of chimeric antibodies were summarized in Table 10.

TABLE 10 AC B_(max) EC₅₀ c208F2  981 6.7E−10 c212A11 991 6.7E−1.0 c214F8  1069 5.0E−10 c219D6  993 4.7E−10 c213B10 1103 4.4E−10

Example 3: Confirmation of Antibody Specificity by Using Either IGF-1R or IR Transfected Cells or IM9 Cells that Express Significant Levels of IR

In order to confirm the specificity of the generated antibodies for IGF-1R versus IR, stable transfectants expressing either hIGF-1R or hIR were evaluated by FACS analyses. Briefly, increasing concentrations of chimeric mAbs were incubated with cells for 20 min at 4° C. in FACS buffer (PBS, 0.1% BSA, 0.01% NaN₃). Cells were then washed 3 times and incubated with the appropriate secondary antibody coupled with Alexa 488 before being incubated for 20 additional minutes at 4° C. in the dark and then washed 3 times in FACS buffer. The binding of anti-IGF-1R antibodies was immediately performed on viable cells which were identified using propidium iodide (that stains dead cells). The binding EC₅₀ expressed in molarity (M) was calculated using a nonlinear regression analysis (GraphPad Prims 4.0).

Titration curves obtained on the hIGF-1R transfected cell line (FIG. 2A) versus untransfected cells (FIG. 2B) confirmed the binding specificity of chimeric Abs for the human IGF-1R. EC₅₀ and B_(max) values were summarized in Table 11.

TABLE 11 Ac B_(max) EC₅₀ (M) c208F2  2008 3.2E−10 c212A11 2513 4.4E−10 c214F8  2094 2.7E−10 c219D6  2521 5.5E−10 c213B10 2029 3.3E−10

In order to verify the absence of binding of both murine and chimeric antibodies on hIR, a stable cell line expressing the human IR (hIR) was used. The recognition of human cell surface hIR by both murine and chimeric Ab was performed by FACS analyses. Increasing concentration of either the murine or the chimeric mAbs were incubated on the hIR transfected cell line for 20 minutes at 4° C. in FACS buffer (PBS, 0.1% BSA, 0.01% NaN₃). Cells were then washed 3 times and incubated with the appropriate secondary antibody coupled with Alexa 488 before being incubated for 20 additional minutes at 4° C. in the dark and then washed 3 times in FACS buffer. The binding of anti-IGF-1R antibodies was immediately performed on viable cells which were identified using propidium iodide (that stains dead cells). The binding EC₅₀ expressed in molarity (M) was calculated using a nonlinear regression analysis (GraphPad Prims 4.0). The anti-hIR antibody clone GRO5 was used as positive controls. The murine and chimeric 9G4 antibodies were introduced as irrelevant antibodies.

The high level of expression of hIR on cell surface of the transfected cells was confirmed using the commercial anti-hIR antibody GRO5 (FIGS. 3A and 3B). Even using high concentrations of either the murine (FIG. 3A) or the chimeric (FIG. 3B) hIGF-1R Abs, no binding on cell surface of hIR transfected cells was observed. These results demonstrated that neither murine nor chimeric anti-hIGF-1R Abs did recognized the hIR.

This specificity of recognition of hIGF-1R versus IR has also been demonstrated, by FACS analyses, using IM9 cells, a B-lymphoma cell line that expresses hIR (FIG. 4 ). For this FACS analyses, the protocol was the same as the one described above and murine antibodies were used in order to prevent the cross reactivity of the secondary anti-human Ab (IM9 cells express human Ig on their cell surface). Results presented in FIG. 4 demonstrated once again that the expected signal was observed using the GRO5 anti-hIR antibody while none of the murine antibody evaluated displayed any significant binding signal on this cell line.

Example 4: Antibody Binding to the Monkey Native IGF-1R by FACS and BIACORE Analyses

One of the first pre-requisite for regulatory toxicology studies is to find a relevant animal specie in order to evaluate the selected compound. As the series of antibodies described herein is not able to recognize murine IGF-1R, the most likely specie for toxicological evaluation is the non human primate (NHP).

In order to evaluate the binding of anti-IGF-1R antibodies on monkey IGF-1R, the binding of both murine and chimeric anti-hIGF-1R antibodies was first evaluated by FACS analyses on COS-7 cell line using increasing antibody concentrations. Cells (1×10⁶ cells/ml) were incubated with anti-IGF-1R antibodies for 20 minutes at 4° C. in FACS buffer (PBS, 0.1%, BSA, 0.01% NaN₃). Then, cells were washed 3 times and incubated with the appropriate secondary antibody coupled with Alexa 488 before being incubated for 20 additional minutes at 4° C. in the dark and finally washed 3 times in FACS buffer. The binding of anti-IGF-1R antibodies was immediately evaluated on viable cells identified using propidium iodide (that stains dead cells). The binding EC₅₀ expressed in molarity (M) was calculated using a nonlinear regression analysis (GraphPad Prims 4.0).

The titration curves obtained on the COS-7 monkey cell line showed that, all the anti-hIGF-1R Abs recognized specifically the IGF-1R expressed on the surface of the monkey cell line (FIG. 5A). Determination of the, EC₅₀ for each murine and chimeric Abs showed that the 2 forms compared well regarding to their binding properties on monkey IGF-1R (FIG. 5B). Those results showed that all the generated anti-hIGF-1R recognized the monkey IGF-1R.

A comparison of binding EC₅₀ on COS-7 cells versus transfected IGF-1R cells was performed in order to verify the magnitude of chimeric antibody recognition on human versus monkey IGF-1R. Results shown in FIG. 5C demonstrated a similar recognition of human and monkey IGF-1Rs by all antibodies.

In order to confirm the recognition on another type of monkey, cells were transfected with the IGF-1R form Cynomolgus monkey to produce soluble monkey IGF-1R ECD and BIACORE experiments were performed with one of the chimeric antibodies (c208F2) in order to compare its binding properties either the hIGF-1R or the Cynomolgus IGF-1R.

The recognition experiments were run on a BIACOREX100 device using a CM5 sensor chip activated by an anti-Tag His antibody (His capture kit GE Healthcare catalogue number 28-9950-56). More than 11000 RU of antibodies are chemically grafted on the carboxymethyldextan matrix using the amine kit chemistry. The experiments were carried out at 25° C. with a flow rate of 30 μl/min using the HBS-EP buffer (GE Healthcare) as the running and sample dilution buffer. The single cycle kinetic scheme was used to defined the kinetic parameters of the binding of the chimeric form of the 208F2 antibody (c208F2) on hIGF-1R compared to Macaca IGF-1R

A solution of a soluble recombinant version of the IGF1R hetero-tetramere composed of 2α chains and the extracellular domains of 2β chains expressed with an additional C-terminal 10-His tag, based either on the sequence of the human (R&D Systems catalogue number 305-GR-50) or of the one of cynomolgus (produced in house) was injected 1 minute on the second flowcell at a dilution defined to capture around 160 RU of antigen. After the capture phase, either the running buffer was injected 5 times (90 s each injection) or a growing range of 5 concentrations of c208F2 were injected (90 s each injection) on both flowcells. At the end of the fifth injection the running buffer was passed in order to define the dissociation rate.

The surface was then regenerated with an injection of a 10 mM Glycine, HCl pH 1.5 buffer during 30 s.

The computed signal corresponds to the difference between the response of the flowcell 2 (with captured IGF-1R) and the response of the flowcell 1 (without any IGF-1R molecules) (FIG. 6 ).

For each IGF1R molecule (human or cyno), the signal due to the injections of the growing range of concentrations of c208F2 was corrected by subtraction of the signal obtained with the 5 injections of the buffer (double reference). The resulting sensorgrams were analysed using the Biaevaluation software with a 1:1 model. The kinetic rates are evaluated either independently (2 kinetics rates of the binding of c208F2 on each IGF-1R) or commonly (the same kinetic rates of the binding of c208F2 on the human and the cynomolgus IGF1R). The quality of the fitting was assessed by a Chi2/Rmax ratio lower than 0.05 RU.

The kinetics rates of the binding (see Table 12) defined separately for each IGF-1R are close and a fitting of both sensorgrams with the same kinetic rates is of good quality.

The c208F2 antibody recognizes as well the recombinant human and cynomolgus IGF-1Rs with a dissociation constant (KD) about 0.2 nM. The affinities defined in tis study correspond to the functional affinities (avidities) of the antibodies for a level of captured human and cynomolgus IGF-1R around 160 RU.

TABLE 12 IGF1R kon [1/M · s] koff [1/s] Kd [nM] Chi2/Rmax human 1.52E+06 3.40E−04 0.23 0.045 cynomogus 1.85E+06 3.10E−04 0.17 0.032 Hum. & Cyno. 1.52E+06 3.33E−04 0.22 0.039

Example 5: Intrinsic Effect of Generated Antibodies on IGF-1R Phosphorylation

It is well known that antibodies could induce an agonistic effect when they bind to tyrosine kinase receptors. As we would not like to select such agonist antibodies, the evaluation of hIGF-1R phosphorylation was studied using the chimeric antibodies.

For that purpose, MCF-7 cells were incubated in serum-free medium overnight. Then, either IGF-1 (100 nM) or Abs to be tested were added (10 μg/ml) for 10 minutes at 37° C. Medium was discarded and cells were scraped in a lysis buffer (pH 7.5) containing 10 mM Tris HCl buffer (pH 7.5), 15% NaCl (1 M), 10% detergent mix (10 mM Tris-HCl, 10% Igepal lysis buffer) (Sigma Chemical Co.), 5% sodium deoxycholate (Sigma Chemical Co.), 1 protease inhibitor cocktail complete TM tablet (Roche), 1% phosphatase inhibitor Cocktail Set II (Calbiochem), for 90 mM at 4° C. The lysates were clarified by centrifugation at 4° C., heated for 5 mM at 100° C. and kept at −20° C. or directly loaded on 4-12% SDS-PAGE gels. Incubation of the primary antibody was performed for 2 hr at room temperature and then incubation with HRP-linked secondary antibodies was done for 1 hr at room temperature. Membranes were washed in TBST prior to visualization of proteins with ECL. Blots were quantified using Image J software. Phospho-protein values were normalized with GAPDH. Phosphorylation of hIGF-1R in response to IGF-1 was considered as 100% of stimulation. The effect of anti-hIGF-1R Abs on the phosphorylation of hIGF-1R was determined as % of phosphorylation induced by IGF-1.

The results described in FIG. 7 represent the mean of the % of pIGF-1R in response to the chimeric anti-IGF-1R Abs of 3 independent experiments +/−S.D. compared to IGF-1. As illustrated no significant or minor (<10%) phosphorylation of hIGF-1R was detected when MCF-7 cells were incubated with 10 μg of anti-IGF-1R Abs.

Example 6: Inhibition of IGF-1R Phosphorylation in Response to IGF-1 by Murine IGF-1R Antibodies

In order to characterize the selected antibodies, their ability to inhibit IGF1-induced phosphorylation was studied. For that purpose, MCF-7 cells were incubated in serum-free medium overnight. Then, cells were incubated for 5 minutes with murine anti-hIGF-1R Abs before addition of IGF-1 for 2 minutes at 37° C. Medium was discarded and cells were scraped in a lysis buffer (pH 7.5) containing 10 mM Tris HCl buffer (pH 7.5), 15% NaCl (1 M), 10% detergent mix (10 mM Tris-HCl, 10% Igepal lysis buffer) (Sigma Chemical Co.), 5% sodium deoxycholate (Sigma Chemical Co.), 1 protease inhibitor cocktail complete TM tablet (Roche), 1% phosphatase inhibitor Cocktail Set II (Calbiochem), for 90 min at 4° C. The lysates were clarified by centrifugation at 4° C., heated for 5 min at 100° C. and kept at −20° C. or directly loaded on 4-12% SDS-PAGE gels. Incubation of the primary antibody was performed for 2 h at room temperature and then incubation with HRP-linked secondary antibodies was performed for 1 hr at room temperature. Membranes were washed in TBST prior to visualization of proteins with ECL. Blots were quantified using Image J software. Phospho-protein values were normalized with GAPDH. Phosphorylation of hIGF-1R in response to IGF-1 was considered as 100% of stimulation. The effect of anti-hIGF-1R Abs on the phosphorylation of hIGF-1R was determined as % of phosphorylation induced by IGF-1.

All anti-IGF-1R Abs inhibited strongly hIGF-1R phosphorylation in response to IGF-1 (decrease >80%) (FIG. 8 ). The best inhibitors of IGF1-induced phosphorylation of hIGF-1R are the m208F2, m212A11 and m214F8 Mabs.

Example 7: Study of IGF-1R Internalization after Binding of the Generated IGF-1R Antibodies by FACS Analyses

MCF-7 cells were incubated with 10 μg/ml of chimeric antibodies at 4° C. for 20 min. Then, cells were washed and incubated at 4° C. or 37° C. for 4 h. The quantity of cell-surface bound antibody was determined using a secondary antibody. The ΔMFI defined as the difference between MFI measured at 4° C. and MFI measured at 37° C. after a 4 hour incubation time corresponded to the quantity of internalized A_(b). The ΔMFI was presented in FIG. 9 and Table 11. The percentage of internalization at 10 μg/ml of Ab were calculated as followed 100*(MFI at 4° C.-MFI at 37° C.)/MFI at 4° C. and presented in Table 13.

TABLE 13 Abs % Internalization ΔMFI ΔMFI_EC₅₀ c208F2  83 288 1.8E−10 c212A11 80 322 2.7E−10 c214F8  87 403 2.2E−10 c219D6  80 353 4.4E−10 c231B10 85 369 2.3E−10

In order to determine whether antibodies that also recognized the monkey IGF-1R were able to internalize this receptor, the same internalization experiment was performed. Results summarized in Table 14 demonstrated that all tested antibodies were able to mediate monkey IGF-1R internalization.

TABLE 14 Murine Abs Chimeric Abs Abs ΔMFI % internalisation ΔMFI % internalisation 208F2  53 74 52 67 212A11 83 73 98 75 214F8  76 71 98 72 219D6  80 71 102 74 213B10 84 74 101 73

The kinetic of cell surface bound antibody decrease was further evaluated. For that purpose, MCF-7 cells were seeded in 96-well plates and incubated with 10 μg/ml of murine for 20 min at 4° C. Cells were then washed to remove unbound antibody and in media at 37° C. for 10, 20, 30, 60 or 120 min. At each time point, cells were centrifuged and then surface labeled on ice with a secondary anti-mouse IgG-Alexa488 to determine the amount of antibody remaining on the cell surface. The fluorescence intensity for each murine Ab and for each time point was normalized by the signal at 4° C. (% remaining IGF-1R) and fitted to an exponential decay to determine the half life (t1/2). t1/2 was considered as the time needed to obtain a decrease of 50% of the signal. As illustrated in FIG. 10 , the surface level of all murine Abs dropped rapidly over the first 30 min and the decrease was almost maximum after 60 min of incubation (FIG. 10A). The calculated half life was comprised between 10 to 18 min according to the murine Ab (FIG. 10B).

In order to validate that the decrease of the cell surface signal was due to Ab internalization and not due to receptor shedding, cells were incubated with murine Abs for 0, 30 and 60 min at 37° C. (FIG. 11 ). Cells were then fixed and permeabilized or not in order to determine cell surface bound antibody (w/o permeabilization) and total antibody signal corresponding to cell-surface bound+internalized Ab (with permeabilization). The quantity of internalized Ab (cytoplasmic) was determined as follow: MFI after permabilization—MFI w/o permeabilization. This experiment showed that the decrease of cell-surface bound Ab was due to an increase of cytoplasmic Abs demonstrating that Abs were internalized (FIG. 11 ). In addition, the degradation of the Abs started after 1 h of incubation as indicated by the decrease of the signal after permeabilization (Total).

Example 8: Study of IGF-1R Internalization after Binding of the Generated IGF-1R Antibodies by Confocal Analyses

To further confirm antibodies internalization, confocal microscopy was done to assess the subcellular distribution of antibodies following cellular trafficking. Cells were incubated with anti-hIGF-1R Abs 37° C., fixed and permeabilized. Therefore, cells were stained using a secondary antibody Alexa-488 and with rabbit anti-Lamp-1 antibody that was revealed using a secondary anti-Rabbit IgG Alexa 555. Before incubation at 37° C., the murine 208F2 Ab was localized on the membrane of MCF-7 cells (FIG. 12A). No colocalization with the lysosome marker, lamp-1 was noted using the colocalization highliter plug-in of the Image J software. The cell surface bound antibody decreased dramatically after 15 min of incubation at 37° C. Concomitantly to the decrease of the cell surface bound antibody, intracellular antibody was detected into vesicles. Rare colocalization with lamp-1 could be observed. After 30 min of incubation, the cell surface bound antibody was hardly detected. However, the colocalization of the Ab into lysosome increased. After 1 h of incubation, the intracellular Ab staining decreased as well as the number of colocalization with lamp-1. This kinetic of cell surface bound antibody and its intracellular accumulation correlated with the kinetic of antibody surface decay measure by FACS. In addition, as already described with FACS studies, the degradation of murine Abs started after 1 h of incubation by confocal microscopy.

The internalization of all other hIGF-1R murine antibodies and their colocalization with Lamp-1 was also assessed (FIG. 12B). After 30 min of incubation at 37° C., intracellular antibody was detected and colocalization with lamp-1 could be observed indicating that all selected anti-IGF-1R antibodies were effectively internalized into lysosomes.

Example 9: Inhibition of Abs Degradation Using Lysosome Inhibitor, Bafilomycin A1

In order to confirm that antibodies reached the lysosome were they are degraded, cells were treated or not with bafilomycine A1, a potent inhibitor of lysosome functions. Cells were then incubated with 10 μg/ml of Ab to be tested at 4° C., washed and incubated for 2 h at 37° C. The internalized Ab was detected after cell permeabilisation using a secondary anti-mouse IgG-Alexa 488 A_(b). Addition of bafilomycine A1 prevented the degradation of intracellular Ab (FIG. 13 ) indicating that Abs were effectively internalized and degraded into lysosomes.

Example 10: Effect of pH on Antibody-IGF-1R Binding

As antibodies were selected on the bases of their internalizing potential and shown above to co-localize with early endosomes before entering into the lysosomal compartment, an interesting approach consisted in selecting antibodies for which the stability of the A_(b)/hIGF-1R binding was modulated regarding to pH environment and preferentially antibodies that dissociated preferentially from IGF-1R when the pH environment became acid. Indeed, the primary difference between early endosomes and lysosomes is their luminal pH: in the endosome compartment the pH is approximately 6 while in the lysosomal compartment the pH is about 4.5.

It is well known that once internalized after ligand binding (IGF1), hIGF-1R returns back to the cell surface through a recycling pathway.

Without being link by a theory, an hypothesis herein described is that antibodies more prone to be released from their target early at acidic pH will probably favour target recycling to the membrane and consequently could be considered as better candidates for ADC approaches. In order to investigate whether some of our antibodies display such a property and to correlate this property to cytotoxic activity, the binding of the murine anti-hIGF-1R Mabs on MCF-7 cell line was done in buffers at different pH. Increasing concentrations of murine mAbs were incubated on MCF-7 cell line for 20 min at 4° C. in different pH ranging from 5 to 8. Cells were then washed 3 times and incubated with the appropriate secondary antibody coupled with Alexa 488 in FACS buffer. Cells were incubated for 20 additional minutes at 4° C. in the dark and then washed 3 times in FACS buffer. The binding of anti-hIGF-1R antibodies was immediately performed on viable cells which were identified using propidium iodide that stained dead cells. The binding EC₅₀ expressed in molarity (M) was calculated using a nonlinear regression analysis (GraphPad Prims 4.0). All murine anti-IGF-1R antibodies selected showed a lower binding capacity at acidic pH as illustrated in FIG. 14 .

Example 11: Evaluation of a Humanized Form of the 208F2 Mab

The binding of the first humanized form of the c208F2 mAb was evaluated on MCF-7, COS-7 and NIH 3T3 IR⁺ cell lines. Increasing concentrations of m208F2, c208F2 or hz208F2 VH3VL3 were added on each cell line for 20 min at 4° C. Cells were then washed and the binding of the tested mAb was revealed using the corresponding secondary antibody. In order to validate the expression of the human IR on the transfected cell line, the commercial anti-hIR antibody clone GRO5 was used and its recognition profile exemplified on (FIG. 15D).

Comparison of the humanized form with either murine or chimeric ones on MCF-7 (FIG. 15A) or monkey COS-7 (FIG. 15B) cells showed close profiles for the 3 tested forms. The humanisation process did not modify the specificity of recognition of the antibody that is perfectly comparable to the murine and chimeric forms regarding to the absence of cross reactivity on the human insulin receptor (FIG. 15C).

The calculated EC₅₀ of the first humanized form of 208F2 on the human cell line MCF-7 and the monkey cell line COS-7 were similar to the one determined with either the murine or the chimeric form of the mAb 208F2.

The capacity of the mAb hz208F2 VH3/VL3 to be internalized was assessed by flow cytometry. MCF-7 cells were incubated with 10 μg/ml of antibodies at 4° C. for 20 min. Then, cells were washed and incubated at 4° C. or 37° C. for 4 h. The quantity of cell-surface bound antibody was determined using a secondary antibody. The ΔMFI defined as the difference between MFI measured at 4° C. and MFI measured at 37° C. after a 4 hour incubation time corresponded to the quantity of internalized A_(b). The ΔMFI was presented in FIG. 16 and Table 13. The percentage of internalization at 10 μg/ml of Ab were calculated as followed 100*(MFI at 4° C.-MFI at 37° C.)/MFI at 4° C. and presented in Table 15. Therefore, the humanized hz208F2 VH3/VL3 had similar binding and internalization properties as the one measured with the corresponding murine and chimeric 208F2 antibodies.

TABLE 15 ΔMFI % internalization m208F2 294 88 o208F2 278 82 Hz208F2 VH3/VL3 344 87

Example 12: Definition of the Dissociation Constant (K_(D)) of the Binding of Five Chimeric Anti-IGF1R Antibodies (c208F2, c213B10, c212A11, c214F8 and c219D6) and a Humanized Version (VH3/VL3) of the 208F2 Antibody on a Soluble Recombinant Human IGF1R

The dissociation constants (K_(D)) of the binding of the antibodies on a recombinant soluble human-IGF1R were defined by the ratio between the dissociation rate (k_(off)) and the association rate (k_(on)). The kinetic experiments were run on a BIACORE X100 device using a CM5 sensor chip activated by a mouse anti-Tag His monoclobnal antibody. Around 12000 RU of antibodies are chemically grafted on the carboxymethyldextan matrix using the amine kit chemistry.

The experiments were carried out at 25° C. with a flow rate of 30 μl/min using the HBS-EP+buffer (GE Healthcare) as the running and sample dilution buffer.

The single cycle kinetic scheme was used to define the kinetic parameters of the binding of the anti-IGF1R antibodies on a soluble recombinant human IGF1R captured by its two C-terminal 10 Histidine-tag.

-   -   1—A solution of a soluble recombinant version of the human IGF1R         hetero-tetramere: 2a chains and the extracellular domains of 2β         chains expressed with an additional C-terminal 10-His tag (R&D         Systems catalogue number 305-GR-50) was injected during one         minute on the second flowcell at a concentration of 10 μg/ml. A         mean of 587 RU (with a standard deviation 24 RU) of the soluble         receptor were captured at each of the 24 cycles realised for         this study.     -   2—After the capture phase, either the running buffer was         injected 5 times (90 s each injection) or a growing range of 5         concentrations of one of the six antibodies was injected (90 s         each injection) on both flowcells. At the end of the fifth         injection the running buffer was passed during 5 minutes in         order to define the dissociation rate.     -   3—The surface was then generated with an injection of a 10 mM         Glycine, HCl pH 1.5 buffer during 45 s.

The computed signal corresponds to the difference between the response of the flowcell 2 (with captured IGF1R) and the response of the flowcell 1 (without any IGF1R molecules).

For each IGF1R the signal due to the injections the growing range of concentrations of one antibody was corrected by subtraction of the signal obtained with the 5 injections of the buffer (double reference) see FIG. 17 .

The resulting sensorgrams were analysed by the Biaevaluation software with a 1:1 model.

Four experiences were run for each antibody using two different ranges of concentrations: 40, 20, 10, 5 and 2.5 nM for the two first experiments and: 24, 12, 6, 3 and 1.5 nM for the two last experiments run for each antibody.

For the 6 antibodies tested in this experiment the experimental data fitted well with an 1:1 model with significant k_(off) values when the higher concentration was defined as a constant and the other four concentrations are calculated (see FIG. 18 ).

The dissociation constants (K_(D)) calculated as the ratio: k_(off)/k_(on) and the half-live of the complexes calculated as the ratio:Ln(2)/k_(off) are represented in the FIGS. 19 and 20 . They correspond to the mean of the four independent experiments run for each antibodies. The error bars correspond to the standard errors (n=4) of the values.

The dissociation constants are in the range of 10 to 100 pM. The c208F2 antibody presents the weaker affinity (higher dissociation constant value) for the h-IGF1R (with a K_(D) around 75 pM) and its humanized version is at least as good as the chimeric version (with a K_(D) around 60 pM). The four other anti-IGF1R chimeric antibodies present a quite similar affinity for the hIGF1-R (with a K_(D) around 30 pM). The difference of the affinities is principally linked to the dissociation rate or the resultant half life of the complexes. With 208F2 the half-life of the complex is between 2 and 3 hour with the chimeric and the humanized (VH3/VL3) versions. For the four other chimeric antibodies the means half lives are between 7.0 and 9.4 h.

These very slow dissociation kinetics are clearly linked to the bivalent structure of the antibodies which are able to bind simultaneously by both of their Fab arms to two adjacent h-IGF1R molecules. In this case the level of captured IGF1R molecules may have an impact on the dissociation rate. The affinities defined in this study correspond to the functional affinities (or avidities) of the antibodies for a level of captured h-IGF1R around 600 RU. The 3 fold difference of KD observed between data shown above (table 10) and values presented in example 13 is linked to a change of the level of capture of hIGF-1R (600 RU versus 160 RU in example 4).

Example 13: Generation of 1613F12

To generate murine monoclonal antibodies (Mabs) against human extracellular domain (ECD) of the Ax1 receptor, 5 BALB/c mice were immunized 5-times s.c. with 15-20.10⁶ CHO-Ax1 cells and twice with 20 μg of the rh Ax1 ECD. The first immunization was performed in presence of Complete Freund Adjuvant (Sigma, St Louis, Md., USA). Incomplete Freund adjuvant (Sigma) was added for following immunizations.

Three days prior to the fusion, immunized mice were boosted with both 20.10⁶ CHO-Ax1 cells and 20 μg of the rhAx1 ECD with IFA.

To generate hybridomas, splenocytes and lymphocytes were prepared by perfusion of the spleen and by mincing of the proximal lymph nodes, respectively, harvested from 1 out of the 5 immunized mice (selected after sera titration) and fused to SP2/0-Ag14 myeloma cells (ATCC, Rockville, Md., USA). The fusion protocol is described by Kohler and Milstein (Nature, 256:495-497, 1975). Fused cells are then subjected to HAT selection. In general, for the preparation of monoclonal antibodies or their functional fragments, especially of murine origin, it is possible to refer to techniques which are described in particular in the manual “Antibodies” (Harlow and Lane, Antibodies: A Laboratory Manual, Cold Spring Harbor Laboratory, Cold Spring Harbor N.Y., pp. 726, 1988).

Approximately 10 days after the fusion, colonies of hybrid cells were screened. For the primary screen, supernatants of hybridomas were evaluated for the secretion of Mabs raised against the Ax1 ECD protein using an ELISA. In parallel, a FACS analysis was performed to select Mabs able to bind to the cellular form of Ax1 present on the cell surface using both wt CHO and Ax1 expressing CHO cells.

As soon as possible, selected hybridomas were cloned by limit dilution and subsequently screened for their reactivity against the Ax1 ECD protein. Cloned Mabs were then isotyped using an Isotyping kit (cat #5300.05, Southern Biotech, Birmingham, Ala., USA). One clone obtained from each hybridoma was selected and expanded.

ELISA assays are performed as followed either using pure hybridoma supernatant or, when IgG content in supernatants was determined, titration was realized starting at 5 μg/ml. Then a 1/2 serial dilution was performed in the following 11 rows. Briefly, 96-well ELISA plates (Costar 3690, Corning, N.Y., USA) were coated 50 μl/well of the rh Ax1-Fc protein (R and D Systems, cat No. 154-AL) or rhAx1 ECD at 2 μg/ml in PBS overnight at 4° C. The plates were then blocked with PBS containing 0.5% gelatin (#22151, Serva Electrophoresis GmbH, Heidelberg, Germany) for 2 h at 37° C. Once the saturation buffer discarded by flicking plates, 50 μl of pure hybridoma cell supernatants or 50 μl of a 5 μg/ml solution were added to the ELISA plates and incubated for 1 h at 37° C. After three washes, 50 μl horseradish peroxidase-conjugated polyclonal goat anti-mouse IgG (#115-035-164, Jackson Immuno-Research Laboratories, Inc., West Grove, Pa., USA) was added at a 1/5000 dilution in PBS containing 0.1% gelatin and 0.05% TWEEN 20 (w:w) for 1 h at 37° C. Then, ELISA plates were washed 3-times and the TMB (#UP664782, Uptima, Interchim, France) substrate was added. After a 10 min incubation time at room temperature, the reaction was stopped using 1 M sulfuric acid and the optical density at 450 nm was measured.

For the selection by flow cytometry, 10⁵ cells (CHO wt or CHO-Ax1) were plated in each well of a 96 well-plate in PBS containing 1% BSA and 0.01% sodium azide (FACS buffer) at 4° C. After a 2 min centrifugation at 2000 rpm, the buffer was removed and hybridoma supernatants or purified Mabs (1 μg/ml) to be tested were added. After 20 min of incubation at 4° C., cells were washed twice and an Alexa 488-conjugated goat anti-mouse antibody 1/500° diluted in FACS buffer (#A11017, Molecular Probes Inc., Eugene, USA) was added and incubated for 20 min at 4° C. After a final wash with FACS buffer, cells were analyzed by FACS (Facscalibur, Becton-Dickinson) after addition of propidium iodide to each tube at a final concentration of 40 μg/ml. Wells containing cells alone and cells incubated with the secondary Alexa 488-conjugated antibody were included as negative controls. Isotype controls were used in each experiment (Sigma, ref M90351MG). At least 5000 cells were assessed to calculate the mean value of fluorescence intensity (MFI).

The hybridoma producing the 1613F12 was selected as a candidate.

Example 14: Humanization of 1613F12

The use of mouse antibodies (Mabs) for therapeutic applications in humans generally results in a major adverse effect, patients raise a human anti-mouse antibody (HAMA) response, thereby reducing the efficacy of the treatment and preventing continued administration. One approach to overcome this problem is to humanize mouse Mabs by replacing mouse sequences by their human counterpart but without modifying the antigen binding activity. This can be achieved in two major ways: (i) by construction of mouse/human chimeric antibodies where the mouse variable regions are joined to human constant regions (Boulianne et al., 1984) and (ii) by grafting the complementarity determining regions (CDRs) from the mouse variable regions into carefully selected human variable regions and then joining these “re-shaped human” variable regions to human constant regions (Riechmann et al., 1988).

14.1 Humanization of the Light Chain Variable Domain VL

As a preliminary step, the nucleotide sequence of 1613F12 VL was compared to the murine germline gene sequences part of the IMGT database (<http://www.imgt.org>). Murine IGKV16-104*01 and IGKJ5*01 germline genes were identified. In order to identify the best human candidate for the CDR grafting, the human germline gene displaying the best identity with 1613F12 VL murine sequence has been searched. With the help of the IMGT database analyses tools, a possible acceptor human V regions for the murine 1613F12 VL CDRs was identified: IGKV1-27*01 and IGKJ4*02. In order to perform the humanization to the light chain variable domain each residue which is different between the human and mouse sequences was given a priority rank order. These priorities (1-4) were used to create 11 different humanized variants of the light chain variable region with up to 14 backmutations.

FR1-IMGT CDR1-IMGT FR2-IMGT 1613F12VL DVQITQSPSYLATSPGETITINCRAS KSI......SKY LAWYQKKPGKTNKLLIY Homsap IGKV1-27*01 DIQMTQSPSSLSASVGDRVTITCRAS QCI......SNY LAWYQQKPGKVPKLLIY  V I     Y AT P ETI  N       E    TN Priority  1 1     3 34 4 433  2       3    33 hz1613F12 (VL1) DIQMTQSPSSLSASVGDRVTITCRAS KSI......SKY LAWYQQKPGKVPKLLIY hz1613F12 (VL1I2V) DVQMTQSPSSLSASVGDRVTITCRAS KSI......SKY LAWYQQKPGKVPKLLIY hz1613F12 (VL1M4I) DIQITQSPSSLSASVGDRVTITCRAS KSI......SKY LAWYQQKPGKVPKLLIY hz1613F12 (VL2.1) DVQITQSPSSLSASVGDRVTITCRAS KSI......SKY LAWYQQKPGKVPKLLIY hz1613F12 (VL2.1V49T) DVQITQSPSSLSASVGDRVTITCRAS KSI......SKY LAWYQQKPGKTPKLLIY hz1613F12 (VL2.1P50N) DVQITQSPSSLSASVGDRVTITCRAS KSI......SKY LAWYQQKPGKVNKLLIY hz1613F12 (VL2.2) DVQITQSPSSLSASVGDRVTINCRAS KSI......SKY LAWYQQKPGKVPKLLIY hz1613F12 (VL2.2V49T) DVQITQSPSSLSASVGDRVTINCRAS KSI......SKY LAWYQQKPGKTPKLLIY hz1613F12 (VL2.2P50N) DVQITQSPSSLSASVGDRVTINCRAS KSI......SKY LAWYQQKPGKVNKLLIY hz1613F12 (VL2.3) DVQITQSPSSLSASVGDRVTINCRAS KSI......SKY LAWYQEKPGKTNKLLIY hz1613F12 (VL3) DVQITQSPSYLAASVGDTITINCRAS KSI......SKY LAWYQEKPGKTNKLLIY CDR2-IMGT FR3-IMGT 1613F12VL SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLRSSDEAMYCC Homsap IGKV1-27*01 AA.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYYC                              E   F M F Priority                              4   4 4 2  hz1613F12 (VL1) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYYC hz1613F12 (VL1I2V) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYYC hz1613F12 (VL1M4I) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYYC hz1613F12 (VL2.1) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYYC hz1613F12 (VL2.1V49T) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYYC hz1613F12 (VL2.1P50N) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYYC hz1613F12 (VL2.2) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYFC hz1613F12 (VL2.2V49T) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYFC hz1613F12 (VL2.2P50N) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYFC hz1613F12 (VL2.3) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYFC hz1613F12 (VL3) SG.......S TLQSGVP.SRFSGGG..SGTDFTLTISSLQPSDVATYFC CDR3-IMGT FR4-IMGT 1613F12VL QQHHFYPLT FGAGTFLSLK Homsap IGKJ4*02        LT FGGGTKVEIK   A  EL L     (SEQ ID NO: 62) Priority    3 33 4     (SEQ ID NO: 108) hz1613F12 (VL1) QQHHFYPLT FGGGTKVEIK    (SEQ ID NO: 70) hz1613F12 (VL1I2V) QQHHFYPLT FGGGTKVEIK    (SEQ ID NO: 72) hz1613F12 (VL1M4I) QQHHFYPLT FGGGTKVEIK    (SEQ ID NO: 73) hz1613F12 (VL2.1) QQHHFYPLT FGGGTKVEIK    (SEQ ID NO: 74) hz1613F12 (VL2.1V49T) QQHHFYPLT FGGGTKVEIK    (SEQ ID NO: 75) hz1613F12 (VL2.1P50N) QQHHFYPLT FGGGTKVEIK    (SEQ ID NO: 76) hz1613F12 (VL2.2) QQHHFYPLT FGGGTKVEIK    (SEQ ID NO: 77) hz1613F12 (VL2.2V49T) QQHHFYPLT FGGGTKVEIK    (SEQ ID NO: 78) hz1613F12 (VL2.2P50N) QQHHFYPLT FGGGTKVEIK    (SEQ ID NO: 79) hz1613F12 (VL2.3) QQHHFYPLT FGGGTKVEIK    (SEQ ID NO: 80) hz1613F12 (VL3) QQHHFYPLT FGAGTELEIK    (SEQ ID NO: 81)

14.2 Humanization of the Heavy Chain Variable Domain VH

In order to identify the best human candidate for the CDR grafting, the mouse and human germline genes displaying the best identity with 1613F12 VH were searched. The nucleotide sequence of 1613F12 VH was aligned with both mouse and human germline gene sequences by using the sequence alignment software “IMGT/V-QUEST” which is part of the IMGT database. Alignments of amino acid sequences were also performed to verify the results of the nucleotide sequence alignment using the “Align X” software of the VectorNTI package. The alignment with mouse germline genes showed that the mouse germline V-gene IGHV14-3*02 and J-gene IGHJ2*01 are the most homologue mouse germline genes. Using the IMGT database the mouse D-gene germline IGHD1-1*01 was identified as homologous sequence. In order to select an appropriate human germline for the CDR grafting, the human germline gene with the highest homology to 1613F12 VH murine sequence was identified. With the help of IMGT databases and tools, the human IGHV1-2*02 germline gene and human IGHJ5*01 J germline gene were selected as human acceptor sequences for the murine 1613F12 VH CDRs. In order to perform the humanization to the heavy chain variable domain each residue which is different between the human and mouse sequences was given a priority rank order (1-4). These priorities were used to create 20 different humanized variants of the heavy chain variable region with up to 18 backmutations,

FR1-IMGT CDR1-IMGT FR2-IMG2 (1-26) (27-38) (39-55) 1613F12 EVNLQQSGA.ELVKPGASVKLSCTAS GFNI....RDTY IHWVKQRPRQGLEWIGR Homsap IGHV1-2*02 QVQLVQSGA.EVKKPGASVKVSCKAS GYTF....TGYY MHWVRQAPGQGLEWMGW E H Q      LV      L T I   K R E     I R Priority 3 2 3      33      3 3 1   3 4 4     3 2 hz1613F12 (VH1) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY MHWVRQAPGQGLEWMGW hz1613F12 (VH1M39I) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY IHWVRQAPGQGLEWMGW hz1613F12 (VH1W55RN66K) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY MHWVRQAPGQGLEWMGR hz1613F12 (VH1Y84S) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY MHWVRQAPGQGLEWMGW hz1613F12 (VH1S85N) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY MHWVRQAPGQGLEWMGW hz1613F12 (VH1I84NS85N) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY MHWVRQAPGQGLEWMGW hz1613F12 (VH2.1) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY IHWVRQAPGQGLEWMGW hz1613F12 (VH2.1Q3H) QVHLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY IHWVRQAPGQGLEWMGW hz1613F12 (VH2.1W55R) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY IHWVRQAPGQGLEWMGR hz1613F12 (VH2.1N66K) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY IHWVRQAPGQGLEWMGW hz1613F12 (VH2.1W55RN66K) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY IHWVRQAPGQGLEWMGR hz1613F12 (VH2.1R80S) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY IHWVRQAPGQGLEWMGW hz1613F12 (VH2.1N66KR80S) QVQLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY IHWVRQAPGQGLEWMGW hz1613F12 (VH2.2) QVHLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY IHWVRQAPGQGLEWMGW hz1613F12 (VH2.2M89L) QVHLVQSGA.EVKKPGASVKVSCKAS GFNI....RDTY IHWVRQAPGQGLEWMGW hz1613F12 (VH2.3) QVQLQQSGA.EVKKPGASVKLSCTAS GFNI....RDTY IHWVRQAPGQGLEWMGW hz1613F12 (VH2.3W55R) QVQLQQSGA.EVKKPGASVKLSCTAS GFNI....RDTY IHWVRQAPGQGLEWMGR hz1613F12 (VH2.3Q3HW55R) QVHLQQSGA.EVKKPGASVKLSCTAS GFNI....RDTY IHWVRQAPGQGLEWMGR hz1613F12 (VH2.4) QVQLQQSGA.EVKKPGASVKLSCTAS GFNI....RDTY IHWVRQAPGQGLEWIGR hz1613F12 (VH3) EVHLQQSGA.ELVKPGASVKLSCTAS GFNI....RDTY IHWVKQAPGQGLEWIGR CDR2-IMGT  FR3-IMGT (56-65) (66-104) 1613F12 LDPA..NGHT KYGPNFQ.GRATMTSDTSSNTAYLQLSSLTSDDTAVYYC Homsap IGHV1-2*02 INPN..SGGT NYAQNFQ.GRVTMTRDTSISTAYNELSRLRSDDTAVYYC K GPN     A S     SN   LQ  S T E Priority 2 344     4 2     11   33  4 4 4 hz1613F12 (VH1) LDPA..NGHT NYAQNFQ.GRVTMTRDTSISTAYNELSRLRSDDTAVYYC hz1613F12 (VH1M39I) LDPA..NGHT NYAQNFQ.GRVTMTRDTSISTAYNELSRLRSDDTAVYYC hz1613F12 (VH1W55RN66K) LDPA..NGHT KYAQNFQ.GRVTMTRDTSISTAYNELSRLRSDDTAVYYC hz1613F12 (VH1Y84S) LDPA..NGHT NYAQNFQ.GRVTMTRDTSSSTAYNELSRLRSDDTAVYYC hz1613F12 (VH1S85N) LDPA..NGHT NYAQNFQ.GRVTMTRDTSINTAYNELSRLRSDDTAVYYC hz1613F12 (VH1I84NS85N) LDPA..NGHT NYAQNFQ.GRVTMTRDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.1) LDPA..NGHT NYAQNFQ.GRVTMTRDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.1Q3H) LDPA..NGHT NYAQNFQ.GRVTMTRDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.1W55R) LDPA..NGHT NYAQNFQ.GRVTMTRDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.1N66K) LDPA..NGHT KYAQNFQ.GRVTMTRDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.1W55RN66K) LDPA..NGHT KYAQNFQ.GRVTMTRDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.1R80S) LDPA..NGHT NYAQNFQ.GRVTMTSDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.1N66KR80S) LDPA..NGHT KYAQNFQ.GRVTMTSDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.2) LDPA..NGHT KYAQNFQ.GRVTMTSDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.2M89L) LDPA..NGHT KYAQNFQ.GRVTMTSDTSSNTAYLELSRLRSDDTAVYYC hz1613F12 (VH2.3) LDPA..NGHT KYAQNFQ.GRVTMTSDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.3W55R) LDPA..NGHT KYAQNFQ.GRVTMTSDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.3Q3HW55R) LDPA..NGHT KYAQNFQ.GRVTMTSDTSSNTAYNELSRLRSDDTAVYYC hz1613F12 (VH2.4) LDPA..NGHT KYAQNFQ.GRVTMTSDTSSNTAYLELSRLRSDDTAVYYC hz1613F12 (VH3) LDPA..NGHT KYGQNFQ.GRVTMTSDTSSNTAYLQLSRLRSDDTAVYYC CDR3-IMGT FR4-IMGT 1613F12VH ARGAYYYGSSGLFYFDY WGQGTTLSVSS     (SEQ ID NO: 63) Homsap IGHJ5*01 WGQGTLVTVSS     (SEQ ID NO: 109)      TLS Priority      444 hz1613F12 (VH1) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 82) hz1613F12 (VH1M39I) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 84) hz1613F12 (VH1W55RN66K) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 85) hz1613F12 (VH1Y84S) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 86) hz1613F12 (VH1S85N) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 87) hz1613F12 (VH1I84NS85N) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 88) hz1613F12 (VH2.1) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 89) hz1613F12 (VH2.1Q3H) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 90) hz1613F12 (VH2.1W55R) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 91) hz1613F12 (VH2.1N66K) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 92) hz1613F12 (VH2.1W55RN66K) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 93) hz1613F12 (VH2.1R80S) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 94) hz1613F12 (VH2.1N66KR80S) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 95) hz1613F12 (VH2.2) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 96) hz1613F12 (VH2.2M89L) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 97) hz1613F12 (VH2.3) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 98) hz1613F12 (VH2.3W55R) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 99) hz1613F12 (VH2.3Q3HW55R) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 100) hz1613F12 (VH2.4) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 101) hz1613F12 (VH3) ARGAYYYGSSGLFYFDY WGQGTLVTVSS     (SEQ ID NO: 102)

Example 15: Ax1 Binding Specificity

In this example, the binding of 1613F12 was first studied on the rhAx1-Fc protein. Then, its binding on the two other members of the TAM family, rhDtk-Fc and rhMer-Fc, was studied.

Briefly, the recombinant human Ax1-Fc (R and D systems, cat No. 154AL/CF), rhDtk (R and D Systems, cat No. 859-DK) or rhMer-Fc (R and D Systems, cat No. 891-MR) proteins were coated overnight at 4° C. to Immulon II 96-well plates and, after a 1 h blocking step with a 0.5% gelatine solution, 1613F12 was added for an additional 1 h at 37° C. at starting concentration of 5 μg/ml (3.33 10⁻⁸M). Then ½ serial dilutions were done over 12 columns. Plates were washed and a goat anti-mouse (Jackson) specific IgG-HRP was added for 1 h at 37° C. Reaction development was performed using the TMB substrate solution. The isotype control antibody mIgG1 and the commercial anti-Ax1 Mab 154 antibody were also used in parallel. Coating controls were performed in presence of a goat anti-human IgG Fc polyclonal serum labelled with HRP (Jackson, ref 109-035-098) and/or in presence of a HRP-coupled anti-Histidine antibody (R and D Systems, ref: MAB050H).

Results are represented in FIGS. 24A, 24B and 24C, respectively.

This example shows that 1613F12 only binds to the rhAx1-Fc protein and does not bind on the two other members of the TAM family, rhDtk or rhMer. No cross-specificity of binding of 1613F12 is observed between TAM members. No non specific binding was observed in absence of primary antibody (diluant). No binding was observed in presence of the isotype control antibody.

Example 16: 1613F12 Recognized the Cellular Form of Ax1 Expressed on Human Tumor Cells

Cell surface Ax1 expression level on human tumor cells was first established using a commercial Ax1 antibody (R and D Systems, ref: MAB154) in parallel of calibration beads to allow the quantification of Ax1 expression level. Secondly, binding of the cell-surface Ax1 was studied using 1613F12.

For cell surface binding studies, two fold serial dilutions of a 10 μg/ml (6.66 10⁻⁸ M) primary antibody solution (1613F12, MAB154 or mIgG1 isotype control 9G4 Mab) are prepared and are applied on 2.10⁵ cells for 20 min at 4° C. After 3 washes in phosphate-buffered saline (PBS) supplemented with 1% BSA and 0.01% NaN₃, cells were incubated with secondary antibody Goat anti-mouse Alexa 488 (1/500° dilution) for 20 minutes at 4° C. After 3 additional washes in PBS supplemented with 1% BSA and 0.1% NaN₃, cells were analyzed by FACS (Facscalibur, Becton-Dickinson). At least 5000 cells were assessed to calculate the mean value of fluorescence intensity.

For quantitative ABC determination using MAB154, QIFIKIT® calibration beads are used. Then, the cells are incubated, in parallel with the QIFIKIT® beads, with Polyclonal Goat Anti-Mouse Immunoglobulins/FITC, Goat F(ab′)₂, at saturating concentration. The number of antigenic sites on the specimen cells is then determined by interpolation of the calibration curve (the fluorescence intensity of the individual bead populations against the number of Mab molecules on the beads.

16.1. Quantification of Cell-Surface Ax1 Expression Level

Ax1 expression level on the surface of human tumor cells was determined by flow cytometry using indirect immunofluorescence assay (QIFIKIT® method (Dako, Denmark), a quantitative flow cytometry kit for assessing cell surface antigens. A comparison of the mean fluorescence intensity (MFI) of the known antigen levels of the beads via a calibration graph permits determination of the antibody binding capacity (ABC) of the cell lines.

Table 16 presents Ax1 expression level detected on the surface of various human tumor cell lines (SN12C, Calu-1, MDA-MB435S, MDA-MB231, NCI-H125, MCF7, Panc1) as determined using QIFIKIT® using the MAB154 (R and D Systems). Values are given as Antigen binding complex (ABC).

TABLE 16 MCF7 NCI-H125 MDA-MB-435S Panc1 MDA-MB-231 Calu-1 SN12C Tumor Breast NSCLC Breast Pancreas Breast Lung Renal type/organ ABC 71 5 540 17 814 36 809 61 186 >100 000 >100 000 (Qifikit)

Results obtained with MAB154 showed that Ax1 receptor is expressed at various levels depending of the considered human tumor cell.

16.2. Ax1 Detection by 1613F12 on Human Tumor Cells

More specifically, Ax1 binding was studied using 1613F12.

1613F12 dose response curves were prepared. MFIs obtained using the various human tumor cells were then analysed with PRISM software. Data are presented in FIG. 25 .

Data indicate that 1613F12 binds specifically to the membrane Ax1 receptor as attested by the saturation curve profiles. However different intensities of labelling were observed, revealing variable levels of cell-surface Ax1 receptor on human tumor cells. No binding of Ax1 receptor was observed using MCF7 human breast tumor cell line.

Example 17: Validation of hz1613F12 vs. m1613F12

In order to establish whether hz1613F12 was comparable to its murine form, binding experiments were performed by ELISA using rhAx1-Fc protein assays.

In this assay, 96 well plates (Immulon II, Thermo Fisher) were coated with a 5 μg/ml of 1613F12 solution in 1×PBS, overnight at 4° C. After a saturation step, a range of rh Ax1-Fc protein (R and D Systems, ref: 154-AL) is incubated for 1 hour at 37° C. on the coated plates. For the revelation step, a biotinylated-Ax1 antibody (in house product) was added at 0.85 μg/ml for 1 hour at 37° C. This Ax1 antibody belongs to a distinct epitopic group. Then an avidin-horseradish peroxidase solution at 1/2000° in diluent buffer is added to the wells. Then the TMB substrate solution is added for 5 min After addition of the peroxydase stop solution, the absorbance at 405 nm was measured with a microplate reader.

FIG. 26 shows that both murine and humanized versions of 1613F12 bind similarly the rhAx1-Fc protein.

Example 18: 1613F12 Internalization Study Using Fluorescent Immunocytochemistry Labelling

Complementary internalization results are obtained by confocal microscopy using indirect fluorescent labelling method.

Briefly, SN12C tumor cell line was cultured in RMPI1640 with 1% L-glutamine and 10% of FCS for 3 days before experiment. Cells were then detached using trypsin and plated in 6-multiwell plate containing coverslide in RPMI1640 with 1 L-glutamine and 5 FCS. The next day, 1613F12 was added at 10 μg/ml. Cells treated with an irrelevant antibody were also included. The cells were then incubated for 1 h and 2 h at 37° C., 5% CO₂. For T 0 h, cells were incubated for 30 minutes at 4° C. to determine antibody binding on cell surface. Cells were washed with PBS and fixed with paraformaldehyde for 15 minutes. Cells were rinsed and incubated with a goat anti-mouse IgG Alexa 488 antibody for 60 minutes at 4° C. to identify remaining antibody on the cell surface. To follow antibody penetration into the cells, cells were fixed and permeabilized with saponin. A goat anti-mouse IgG Alexa 488 (Invitrogen) was used to stained both the membrane and the intracellular antibody. Early endosomes were identified using a rabbit polyclonal antibody against EEA1 revealed with a goat anti-rabbit IgG-Alexa 555 antibody (Invitrogen). Cells were washed three times and nuclei were stained using Draq5. After staining, cells were mounted in Prolong Gold mounting medium (Invitrogen) and analyzed by using a Zeiss LSM 510 confocal microscope.

Photographs are presented in FIGS. 27A-27C.

Images were obtained by confocal microscopy. In presence of the mIgG1 isotype control (9G4), neither membrane staining nor intracellular labelling is observed (FIG. 27A). A progressive loss of the membrane anti-Ax1 labelling is observed as soon as after 1 h incubation of the SN12C cells with 1613F12 (FIG. 27B). Intracellular accumulation of 1613F12 antibody is clearly observed at 1 h and 2 h (FIG. 27C). Intracellular antibody co-localizes with EEA1, an early endosome marker. These photographs confirm the internalization of 1613F12 into SN12C cells.

Example 19: Synthesis of the Drugs of the Invention

The following abbreviations are used in the following examples:

aq. aqueous

ee enantiomeric excess

equiv equivalent

ESI Electrospray ionisation

LC/MS Liquid Chromatography coupled with Mass Spectrometry

HPLC High Performance Liquid Chromatography

NMR Nuclear Magnetic Resonance

sat. saturated

UV ultraviolet

Compound 1 (S)-2-((S)-2-((3-aminopropyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-3-methoxy-1-(S)-2-(1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide, bis trifluoroacetic acid

Compound 1A: (4R,5S)-4-methyl-5-phenyl-3-propanoyl-1,3-oxazolidin-2-one

(4R,5S)-4-methyl-5-phenyl-1,3-oxazolidin-2-one (5.8 g, 32.7 mmol, 1.00 equiv) was dissolved in tetrahydrofuran (THF, 120 mL) in an inert atmosphere. The mixture was cooled to −78° C. and n-butyllithium (14.4 mL) was added drop-wise. After agitation for 30 minutes at −78° C., propanoyl chloride (5.7 mL) was added. Agitation was continued for 30 minutes at −78° C. then overnight at ambient temperature. The reaction mixture was concentrated then re-dissolved in 200 mL of water. The pH of the solution was adjusted to 7 with sodium bicarbonate saturated aqueous solution. This aqueous phase was extracted 3 times with 100 mL of ethyl acetate (EtOAc). The organic phases were combined, dried over sodium sulfate, filtered and concentrated to yield 6.8 g (89%) of compound 1A in the form of a yellow oil.

Compound 1B: tert-butyl (2S)-2-[(1R,2R)-1-hydroxy-2-methyl-3-[(4R,5S)-4-methyl-2-oxo-5-phenyl-1,3-oxazolidin-3-yl]-3-oxopropyl]pyrrolidine-1-carboxylate

Compound 1A (17.6 g, 75.45 mmol, 1.00 equiv) was dissolved in dichloromethane (DCM, 286 mL) in an inert atmosphere. This solution was cooled with an ice bath. Triethylamine (TEA, 12.1 mL, 1.15 equiv) and Bu₂BOTf (78.3 mL, 1.04 equiv) were added drop-wise whilst holding the temperature of the reaction mixture below 2° C. Agitation was continued at 0° C. for 45 minutes, after which the reaction was cooled to −78° C. A solution of tert-butyl (2S)-2-formylpyrrolidine-1-carboxylate (8.5 g, 42.66 mmol, 0.57 equiv) in DCM (42 mL) was added drop-wise. Agitation was continued for 2 hours at −78° C., then for 1 hour at 0° C. and finally 1 hour at ambient temperature. The reaction was neutralised with 72 mL of phosphate buffer (pH=7.2-7.4) and 214 mL methanol, and cooled to 0° C. A solution of 30% hydrogen peroxide in methanol (257 mL) was added drop-wise whilst maintaining the temperature below 10° C. Agitation was continued for 1 hour at 0° C. The reaction was neutralised with 142 mL of water, then concentrated under reduced pressure. The resulting aqueous solution was extracted 3 times with 200 mL EtOAc. The organic phases were combined, dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of EtOAc and petroleum ether (EtOAc:PE=1:8) to yield 13.16 g (40%) of compound 1B in the form of a colourless oil.

Compound 1C: (2R,3R)-3-[(2S)-1[(tert-butoxy)carbonyl]pyrrolidin-2-yl]-3-hydroxy-2-methylpropanoic acid

Compound 1B (13.16 g, 30.43 mmol, 1.00 equiv) was dissolved in THF (460 mL) in the presence of hydrogen peroxide (30% in water, 15.7 mL), then cooled with an ice bath. An aqueous solution of lithium hydroxide (0.4 mol/L, 152.1 mL) was added drop-wise whilst holding the reaction temperature below 4° C. The reaction mixture was agitated 2.5 hours at 0° C. An aqueous solution of Na₂SO₃ (1 mol/L, 167.3 mL) was added drop-wise whist holding the temperature at 0° C. The reaction mixture was agitated 14 hours at ambient temperature, then neutralised with 150 mL of cold sodium bicarbonate saturated solution and washed 3 times with 50 mL of DCM. The pH of the aqueous solution was adjusted to 2-3 with a 1M aqueous solution of KHSO₄. This aqueous solution was extracted 3 times with 100 mL of EtOAc. The organic phases were combined, washed once with saturated NaCl solution, dried over sodium sulfate, filtered and concentrated to yield 7.31 g (88%) of compound 1C in the form of a colourless oil.

Compound 1D: (2R,3R)-3-[(2S)-1-[(tert-butoxy)carbonyl]pyrrolidin-2-yl]-3-methoxy-2-methylpropanoic acid

Compound 1C (7.31 g, 26.74 mmol, 1.00 equiv) was dissolved in an inert atmosphere in THF (135 mL) in the presence of iodomethane (25.3 mL). The reaction medium was cooled with an ice bath after which NaH (60% in oil, 4.28 g) was added in portions. The reaction was left under agitation 3 days at 0° C. and then neutralised with 100 mL of sodium bicarbonate saturated aqueous solution and washed 3 times with 50 mL ether. The pH of the aqueous solution was adjusted to 3 with 1M aqueous KHSO₄ solution. This aqueous solution was extracted 3 times with 100 mL of EtOAc. The organic phases were combined, washed once with 100 mL of Na₂S₂O₃ (5% in water), once with NaCl-saturated solution, then dried over sodium sulfate, filtered and concentrated to yield 5.5 g (72%) of compound 1D in the form of a colourless oil.

Compound 1E: N-methoxy-N-methyl-2-phenylacetamide

2-phenylacetic acid (16.2 g, 118.99 mmol, 1.00 equiv) was dissolved in dimethylformamide (DMF, 130 mL) then cooled to −10° C. Diethyl phosphorocyanidate (DEPC, 19.2 mL), methoxy(methyl)amine hydrochloride (12.92 g, 133.20 mmol, 1.12 equiv) and triethylamine (33.6 mL) were added. The reaction mixture was agitated 30 minutes at −10° C. then 2.5 hours at ambient temperature. It was then extracted twice with 1 litre of EtOAc. The organic phases were combined, washed twice with 500 mL of NaHCO₃ (sat.), once with 400 mL of water, then dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with an EtOAc and PE mixture (1:100 to 1:3) to yield 20.2 g (95%) of compound 1E in the form of a yellow oil.

Compound 1F: 2-phenyl-1-(1,3-thiazol-2-yl)ethan-1-one

Tetramethylethylenediamine (TMEDA, 27.2 mL) was dissolved in THF 300 mL) in an inert atmosphere, then cooled to −78° C. before the drop-wise addition of nBuLi (67.6 mL, 2.5 M). 2-bromo-1,3-thiazole (15.2 mL) was added drop-wise and agitation was continued 30 minutes at −78° C. Compound 1E (25 g, 139.50 mmol, 1.00 equiv) dissolved in THF (100 mL) was added drop-wise. Agitation was continued for 30 minutes at −78° C. then 2 hours at −10° C. The reaction was neutralised with 500 mL of KHSO₄ (sat.), then extracted 3 times with 1 litre of EtOAc. The organic phases were combined, washed twice with 400 mL water and twice with 700 mL of NaCl (sat.), then dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of EtOAc and PE (1:100 to 1:10) to yield 25 g (88%) of compound 1F in the form of a yellow oil.

Compound 1G: (1R)-2-phenyl-1-(1,3-thiazol-2-yl)ethan-1-ol

In an inert atmosphere, a solution of compound 1F (15 g, 73.8 mmol, 1.00 equiv.) in ether (300 mL) was added drop-wise to (+)—B-chlorodiisopinocampheylborane ((+)-Ipc₂BCl, 110.8 mL). The reaction mixture was agitated 24 hours at 0° C., then neutralised with 300 mL of a (1:1) mixture of NaOH (10% in water) and H₂O₂ (30% in water), and finally extracted three times with 500 mL of EtOAc. The organic phases were combined, washed twice with 300 mL of K₂CO₃ (sat.) and once with 500 mL of NaCl (sat.), then dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of EtOAc and PE (1:20 to 1:2) to yield 6.3 g (42%) of compound 1G in the form of a white solid.

Compound 1H: 2-[(1S)-1-azido-2-phenylethyl]-1,3-thiazole

Compound 1G (6 g, 29.23 mmol, 1.00 equiv.) was dissolved in an inert atmosphere in THF (150 mL) in the presence of triphenylphosphine (13 g, 49.56 mmol, 1.70 equiv.), then cooled to 0° C. Diethylazodicarboxylate (DEAD, 7.6 mL) was added drop-wise, followed by diphenylphosphorylazide (DPPA, 11 mL), the cold bath was then removed and the solution was left under agitation 48 hours at ambient temperature. The medium was concentrated under reduced pressure. The residue was purified on a silica column with a mixture of EtOAc and PE (1:100 to 1:30) to yield 8 g of partly purified compound 1H in the form of a yellow oil. Compound 1H was used as such in the following step.

Compound 1I: tert-butyl N-[(1S)-2-phenyl-1-(1,3-thiazol-2-yl)ethyl]carbamate

Compound 1H (6.5 g, 28.2 mmol, 1.00 equiv) was dissolved in an inert atmosphere in THF (100 mL) in the presence of triphenylphosphine (6.5 g, 33.9 mmol, 1.20 equiv.), and heated to 50° C. for 2 hours Ammonia (70 mL) was then added and heating was continued for 3 hours. The reaction was cooled, neutralised with 500 mL water, then extracted 3 times with 500 mL of EtOAc. The organic phases were combined and extracted twice with 500 mL of 1N HCl. The aqueous phases were combined, brought to pH 8-9 by adding a sodium hydroxide solution (10% in water), then extracted 3 times with 500 mL of DCM. The organic phases were combined, dried over sodium sulfate, filtered and concentrated to yield 4.8 g (83%) of (1S)-2-phenyl-1-(1,3-thiazol-2-yl)ethan-1-amine in the form of a yellow oil. This compound was then protected with a Boc group ((tert-butoxy)carbonyl) so that it could be purified. It was dissolved in an inert atmosphere in 1,4-dioxane (40 mL), then cooled to 0° C. (Boc)₂O (10.26 g, 47.01 mmol, 2.00 equiv) diluted in 20 mL of 1,4-dioxane was added drop-wise. The cold bath was removed and the solution left under agitation overnight at ambient temperature before being neutralised with 300 mL of water and extracted twice with 500 mL of EtOAc. The organic phases were combined, dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of EtOAc and PE (1:100 to 1:20, ee=93%). It was then recrystallized in a hexane/acetone mixture (˜5-10/1, 1 g/10 mL) to yield 6 g (84%) of compound 1I in the form of a white solid (ee>99%).

Compound 1J: tert-butyl (2S)-2S)-[(1R,2R)-1-methoxy-2-methyl-2-[[(1S)-2-phenyl-1-(1,3-thiazol-2-yl)ethyl]carbamoyl]ethyl]pyrrolidine-1-carboxylate

Compound 1I (3 g, 9.86 mmol, 1.00 equiv) was dissolved in an inert atmosphere in 10 mL DCM. Trifluoroacetic acid (TFA, 10 mL) was added and the solution left under agitation overnight at ambient temperature, then concentrated under reduced pressure to yield 2.0 g (64%) of (1S)-2-phenyl-1-(1,3-thiazol-2-yl)ethan-1-amine; trifluoroacetic acid in the form of a yellow oil. This intermediate was re-dissolved in 20 mL of DCM after which compound 1D (1.8 g, 6.26 mmol, 1.05 equiv), DEPC (1.1 g, 6.75 mmol, 1.13 equiv) and diisopropylethylamine (DIEA, 1.64 g, 12.71 mmol, 2.13 equiv) were added. The reaction mixture was left under agitation overnight at ambient temperature, then concentrated under reduced pressure. The residue was purified on a silica column with a mixture of EtOAc and PE (1:100 to 1:3) to yield 2.3 g (81%) of compound 1J in the form of a pale yellow solid.

Compound 1K: (2R,3R)-3-methoxy-2-methyl-N-[(1S)-2-phenyl-1-(1,3-thiazol-2-yl)ethyl]-3-[(2S)-pyrrolidin-2-yl]propanamide; trifluoroacetic acid

Compound 1J (2.25 g, 4.75 mmol, 1.00 equiv) was dissolved in an inert atmosphere in 10 mL of DCM. TFA (10 mL) was added and the solution left under agitation overnight at ambient temperature, then concentrated under reduced pressure to yield 2.18 g (94%) of compound 1K in the form of a yellow oil.

Compound 1L: (2S,3S)-2-(benzylamino)-3-methylpentanoic acid

(2S,3S)-2-amino-3-methylpentanoic acid (98.4 g, 750 mmol, 1.00 equiv) was added at ambient temperature and in portions to a 2N sodium hydroxide solution (375 mL). Benzaldehyde (79.7 g, 751.02 mmol, 1.00 equiv) was quickly added and the resulting solution was agitated 30 minutes. Sodium borohydride (10.9 g, 288.17 mmol, 0.38 equiv) was added in small portions, whilst holding the temperature at between 5 and 15° C. Agitation was continued for 4 hours at ambient temperature. The reaction mixture was diluted with 200 mL of water, then washed twice with 200 mL of EtOAc. The pH of the aqueous solution was adjusted to 7 with a 2N hydrochloric acid solution. The formed precipitate was collected by filtering and gave 149.2 g (90%) of compound 1L in the form of a white solid.

Compound 1M: (2S,3S)-2-[benzyl(methyl)amino]-3-methylpentanoic Acid

Compound 1L (25 g, 112.97 mmol, 1.00 equiv) was dissolved in an inert atmosphere in formic acid (31.2 g) in the presence of formaldehyde (36.5% in water, 22.3 g). The solution was agitated 3 hours at 90° C. then concentrated under reduced pressure. The residue was triturated in 250 mL of acetone, then concentrated. This trituration/evaporation operation was repeated twice with 500 mL of acetone to yield 21.6 g (81%) of compound 1M in the form of a white solid.

Compound 1N: (2S,3S)-2-[benzyl(methyl)amino]-3-methylpentan-1-ol

LiA1H₄ (0.36 g) was suspended in 10 mL of THF in an inert atmosphere at 0° C. Compound 1M (1.5 g, 6.37 mmol, 1.00 equiv) was added in small portions whilst holding the temperature at between 0 and 10° C. The reaction mixture was agitated 2 hours at 65° C., then again cooled to 0° C. before being neutralised with successive additions of 360 μL of water, 1 mL of 15% sodium hydroxide and 360 μL of water. The aluminium salts which precipitated were removed by filtering. The filtrate was dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of EtOAc and PE (1:50) to yield 820 mg (58%) of compound 1N in the form of a pale yellow oil.

Compound 1O: (2 S,3 S)-2-[benzyl(methyl)amino]-3-methylpentanal

Oxalyl chloride (0.4 mL) was dissolved in DCM (15 mL) in an inert atmosphere. The solution was cooled to −70° C. and a solution of dimethylsulfoxide (DMSO (0.5 mL) in DCM (10 mL) was added drop-wise for 15 minutes. The reaction mixture was agitated 30 minutes after which a solution of compound 1N (820 mg, 3.70 mmol, 1.00 equiv) in DCM (10 mL) was added drop-wise for 15 minutes. The reaction mixture was agitated a further 30 minutes at low temperature, then triethylamine (2.5 mL) was slowly added. The reaction mixture was agitated 1 hour at −50° C., the cold bath was then removed and the reaction neutralised with 25 mL of water whilst allowing the temperature to return to normal. The solution was washed once with 30 mL of NaCl-saturated aqueous solution, then dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of EtOAc and PE (1:200) to yield 0.42 g (52%) of compound 10 in the form of a yellow oil.

Compound 1P: (2S,3S)—N-benzyl-1,1-dimethoxy-N,3-dimethylpentan-2-amine

Compound 1O (4.7 g, 21.43 mmol, 1.00 equiv) was dissolved in 20 mL of methanol at 0° C. Concentrated sulfuric acid (4.3 mL) was added drop-wise and agitation was continued for 30 minutes at 0° C. Trimethyl orthoformate (21.4 mL) was added, the cold bath removed and the reaction medium left under agitation for 3 hours at ambient temperature. The reaction medium was diluted with 200 mL of EtOAc, successively washed with 100 mL of 10% Na₂CO₃ and 200 mL of saturated NaCl, then dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 3.4 g (60%) of compound 1P in the form of a pale yellow oil.

Compound 1Q: [[1-(tert-butoxy)ethenyl]oxy](tert-butyl)dimethylsilane

Diisopropylamine (20 g, 186.71 m mol, 1.08 equiv) was dissolved in 170 mL of THF in an inert atmosphere and cooled to −78° C. nBuLi (2.4 M, 78.8 mL) was added drop-wise and the solution agitated 30 minutes at low temperature (to give LDA-lithium diisopropylamide) before adding tert-butyl acetate (20 g, 172.18 mmol, 1.00 equiv). The reaction mixture was agitated 20 minutes at −78° C. before adding hexamethylphosphoramide (HMPA, 25.8 mL) and a solution of tertbutyldimethylchlorosilane (TBDMSCl, 28 g, 185.80 mmol, 1.08 equiv) in 35 mL of THF. Agitation was continued for 20 additional minutes at low temperature, and the cold bath was then removed. The solution was concentrated under reduced pressure. The residue was re-dissolved in 100 mL of water and extracted 3 times with 100 mL of PE. The organic phases were combined, washed once with 500 mL of NaCl-saturated aqueous solution, dried over sodium sulfate, filtered and concentrated. The residue was purified by distillation to yield 16.6 g (83%) of compound 1Q in the form of a colourless oil.

Compound 1R: tert-butyl (3R,4S,5 S)-4-[benzyl(methyl)amino]-3-methoxy-5-methyl heptanoate

Compound 1P (2.0 g, 7.54 mmol, 1.00 equiv) and compound 1Q (2.6 g, 11.28 mmol, 1.50 equiv) were dissolved in 33 mL of DCM in an inert atmosphere. The solution was cooled to 0° C. DMF (1.2 g) was added drop-wise together with a solution of BF₃.Et₂O (2.1 g) in 7.5 mL of DCM. Agitation was continued for 24 hours at 0° C. The reaction medium was washed once with 30 mL of sodium carbonate (10%) and twice with 50 mL of NaCl-saturated aqueous solution, then dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of EtOAc and PE (1:100) to yield 1.82 g (91%) of compound 1R in the form of a yellow oil.

Compound 1S: (3R,4S,5S)-3-methoxy-5-methyl-4-(methylamino)heptanoate hydrochloride

Compound 1R (2.4 g, 6.87 mmol, 1.00 equiv) was dissolved in an inert atmosphere in 35 mL of ethanol in the presence of Pd/C (0.12 g) and concentrated hydrochloric acid (0.63 mL). The nitrogen atmosphere was replaced by a hydrogen atmosphere and the reaction medium was left under agitation 18 hours at ambient temperature. The reaction medium was filtered and concentrated under reduced pressure. The residue was triturated in 50 mL of hexane and the supernatant removed which, after drying under reduced pressure, gave 1.66 g (82%) of compound 1S in the form of a white solid.

Compound 1T: tert-butyl (3R,4S,5S)-4-[2S)-2-[[(benzyloxy)carbonyl]amino]-N,3-dimethylbutanamido]-3-mthoxy-5-methylheptanoate

(2S)-2-[[(benzyloxy)carbonyl]amino]-3-methylbutanoic acid (15 g, 0.40 mmol, 1.00 equiv) was dissolved in 300 mL of DCM in the presence of DIEA (38.3 mL) and bromotripyrrolidinophosphonium hexafluorophosphate (PyBrOP, 32.3 g). The solution was agitated 30 minutes at ambient temperature before adding compound 1S (15.99 g, 0.42 mmol, 1.07 equiv). The reaction medium was agitated 2 hours and then concentrated. The residue was purified in reverse phase (C18) with a mixture of acetonitrile (ACN) and water (30:70 to 100:0 in 40 minutes) to yield 17 g (58%) of compound 1T in the form of a colourless oil.

Compound 1U: tert-butyl (3R,4S,5S)-4-[(2S)-2-amino-N,3-dimethylbutanamido]-3-methoxy-5-methylheptanoate

Compound 1T (76 mg, 0.15 mmol, 1.00 equiv) was dissolved in an inert atmosphere in 10 mL of ethanol in the presence of Pd/C (0.05 g). The nitrogen atmosphere was replaced by a hydrogen atmosphere and the reaction agitated 2 hours at ambient temperature. The reaction medium was filtered and concentrated under reduced pressure to yield 64 mg of compound 1U in the form of a colourless oil.

Compound 1V: (3R,4S,5 S)-4-[(2S)-2-[[(9H-fluoren-9-ylmethoxy)carbonyl]amino]-N,3-dimethylbutanamido]-3-methoxy-5-methylheptanoate

Compound 1U (18.19 g, 50.74 mmol, 1.00 equiv) was dissolved in 400 mL of a 1,4-dioxane/water mixture (1:1) in the presence of sodium bicarbonate (12.78 g, 152 mmol, 3.00 equiv) and 9H-fluoren-9-ylmethyl chloroformate (Fmoc-Cl, 19.69 g, 76 mmol, 1.50 equiv), then agitated 2 hours at ambient temperature. The reaction medium was then diluted with 500 mL of water and extracted 3 times with 200 mL of EtOAc. The organic phases were combined, washed once with 200 mL of NaCl-saturated aqueous solution, dried over sodium sulfate, filtered and concentrated to yield 40 g of partly purified compound 1V in the form of a pale yellow oil.

Compound 1W: (3R,4S,5S)-4-[(2S)-2-[[(9H-fluoren-9-ylmethoxy)carbonyl]amino]-N,3-dimethylbutanamido]-3-methoxy-5-methylheptanoic acid

Compound 1V (40 g, 68.88 mmol, 1.00 equiv) was dissolved in a neutral atmosphere in 600 mL of DCM. TFA (300 mL) was added. The solution was agitated 2 hours at ambient temperature, then concentrated under reduced pressure. The residue was purified on a silica column with a mixture of methanol and DCM (1:10) to yield 23.6 g (65%) of compound 1W in colourless oil form.

Compound 1X: 9H-fluoren-9-ylmethyl N-[(1S)-1-[[(3R,4S,5S)-3-methoxy-1-[(2S)-2-[(1R,2R)-1-methoxy-2-methyl-2-[[(1S)-2-phenyl-1-(1,3-thiazol-2-yl)ethyl]carbamoyl]ethyl]pyrrolidin-1-yl]-5-methyl-1-oxoheptan-4-yl](methyl) carbamoyl]-2-methylpropyl]carbamate

Compound 1W (2.53 g, 4.82 mmol, 1.08 equiv) was dissolved in 20 mL of DCM in the presence of compound 1K (2.18 g, 4.47 mmol, 1.00 equiv), DEPC (875 mg, 5.37 mmol, 1.20 equiv) and DIEA (1.25 g, 9.67 mmol, 2.16 equiv). The reaction mixture was left under agitation overnight at ambient temperature, then successively washed with 50 mL of saturated KHSO₄ and 100 mL of water, dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of methanol and DCM (1:200 to 1:40) to yield 2.8 g (71%) of compound 1X in the form of a pale yellow solid.

Compound 1Y: (2S)-2-amino-N-[(3R,5S)-3-methoxy-1-[2S)-2S)-[(1R,2R)-1-methoxy-2-methyl-2-[[(1S)-2-phenyl-1-(1,3-thiazol-2-yl)ethyl]carbamoyl]ethyl]pyrrolidin-1-yl]-5-methyl-1-oxoheptan-4-yl]-N,3-dimethylbutanamide

Compound 1X (2.8 g, 3.18 mmol, 1.00 equiv) was dissolved in acetonitrile (ACN, 12 mL) in the presence of piperidine (3 mL) and left under agitation 18 hours at ambient temperature. The reaction was neutralised with 50 mL of water, then extracted twice with 100 mL of DCM. The organic phases were combined, dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of methanol and DCM (1:100 to 1:40) to yield 1.2 g (57%) of compound 1Y in the form of a yellow solid.

Compound 1ZA: (2S)-2-[[(tert-butoxy)carbonyl](methyl)amino]-3-methyl butanoic acid

(2S)-2-[[(tert-butoxy)carbonyl]amino]-3-methylbutanoic acid (63 g, 289.97 mmol, 1.00 equiv) was dissolved in an inert atmosphere in THF (1000 mL) in the presence of iodomethane (181 mL). The solution was cooled to 0° C. before adding sodium hydride (116 g, 4.83 mol, 16.67 equiv) in small portions. The reaction mixture was agitated for 1.5 hours at 0° C., the cold bath was then removed and agitation continued for 18 hours. The reaction was neutralised with 200 mL of water and then concentrated under reduced pressure. The residual aqueous phase was diluted with 4 litres of water, washed once with 200 mL of EtOAc and its pH adjusted to between 3 and 4 with a 1N solution of hydrochloric acid. The mixture obtained was extracted 3 times with 1.2 L of EtOAc. The organic phases were combined, dried over sodium sulfate, filtered and concentrated to yield 60 g (89%) of compound 1ZA in the form of a yellow oil.

Compound 1ZB: benzyl (2S)-2-[[(tert-butoxy)carbonyl](methyl)aminol-3-methylbutanoate

Compound 1ZA (47 g, 203.21 mmol, 1.00 equiv) was dissolved in DMF (600 mL) in the presence of Li₂CO₃ (15.8 g, 213.83 mmol, 1.05 equiv). The solution was cooled to 0° C. then benzyl bromide (BnBr 57.9 g, 338.53 mmol, 1.67 equiv) was added drop-wise. The reaction mixture was left under agitation overnight before being neutralised with 400 mL of water and filtered. The solution obtained was extracted twice with 500 mL of EtOAc. The organic phases were combined, dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of EtOAc and PE (1:100 to 1:20) to yield 22.5 g (34%) of compound 1ZB in the form of a yellow oil.

Compound 1ZC: benzyl (2S)-3-methyl-2-(methylamino)butanoate hydrochloride

Compound 1ZB (22.5 g, 70.00 mmol, 1.00 equiv) was dissolved in 150 mL of DCM. Gaseous hydrochloric acid was bubbled. The reaction was agitated 1 hour at ambient temperature and then concentrated under reduced pressure to yield 17 g (94%) of compound 1ZC in the form of a yellow solid.

Compound 1ZD: tert-butyl N-(3,3-diethoxypropyl)carbamate

3,3-diethoxypropan-1-amine (6 g, 40.76 mmol, 1.00 equiv) was dissolved in 1,4-dioxane (30 mL) in the presence of TEA (4.45 g, 43.98 mmol, 1.08 equiv), then cooled to 0° C. (Boc)₂O (9.6 g, 43.99 mmol, 1.08 equiv) diluted in 20 mL of 1,4-dioxane was added drop-wise. The solution was agitated 2 hours at 0° C. then overnight at ambient temperature before being neutralised with 10 mL of water. The pH was adjusted to 5 with HCl (1%). The solution was extracted 3 times with 50 mL of EtOAc. The organic phases were combined, dried over sodium sulfate, filtered and concentrated to yield 8.21 g (81%) of compound 1ZD in the form of a pale yellow oil.

Compound 1ZE: tert-butyl N-(3-oxopropyl) carbamate

Compound 1ZD (8.20 g, 33.15 mmol, 1.00 equiv) was dissolved in 18.75 mL of acetic acid and left under agitation overnight at ambient temperature. The reaction medium was then extracted 3 times with 30 mL of EtOAc. The organic phases were combined, washed 3 times with 30 mL of saturated NaCl solution, dried over sodium sulfate, filtered and concentrated to yield 5 g (87%) of compound 1ZE in the form of a dark red oil.

Compound 1ZF: (2S)-2-[(3[[(tert-butoxy)carbonyl]amino]propyl)(methyl)amino]-3-methylbutanoic acid

Compound 1ZE (2.4 g, 13.86 mmol, 1.00 equiv) was dissolved in 50 mL of THF in the presence of compound 1ZC (3.56 g, 13.81 mmol, 1.00 equiv) and DIEA (9.16 mL, 4.00 equiv). The reaction mixture was agitated 30 minutes at ambient temperature before adding sodium triacetoxyborohydride (5.87 g, 27.70 mmol, 2.00 equiv). Agitation was continued overnight, then the reaction was neutralised with 100 mL of water and extracted 3 times with 50 mL of EtOAc. The organic phases were combined, dried over sodium sulfate, filtered and concentrated. The residue was partly purified on a silica column with a mixture of EtOAc and PE (1:4). The crude product obtained was re-dissolved in 20 mL of methanol in the presence of Pd/C (1.2 g) and hydrogenated for 20 minutes at normal temperature and pressure. The reaction medium was filtered and concentrated under reduced pressure to yield 200 mg (5%) of compound 1ZF in the form of a white solid.

Compound 1ZG: tert-butyl N-(3-[[(1S)-1-[[(1S)-1-1[[(3R,4S,5S)-3-methoxy-1-[(2S)-2-[(1R,2R)-1-methoxy-2-methyl-2-[[(1S)-2-phnyl-1-(1,3-thiazol-2-yl)ethyl]carbamoyl]thyl]pyrrolidin-1-yl]-5-methyl-1-oxoheptan-4yl](methyl) carbamoyl]-2-methylpropyl]carbamoyl]-2 methylpropyl](methyl)amino]propyl) carbamate

Compound 1Y (50 mg, 0.08 mmol, 1.00 equiv) was dissolved in 2 mL of DMF in the presence of compound 1ZF (26.2 mg, 0.09 mmol, 1.20 equiv), DIEA (37.7 mL) and O-(7-azabenzotriazol-1-yl)-N,N,N′,N′-tetramethyluronium hexafluorophosphate (HATU, 43.3 mg, 0.11 mmol, 1.50 equiv). The reaction was left under agitation overnight at ambient temperature, then diluted with 10 mL of water and extracted 3 times with 5 mL of EtOAc. The organic phases were combined, dried over sodium sulfate, filtered and concentrated to yield 100 mg of compound 1ZG in the form of a partly purified colourless oil.

Compound 1ZG (90 mg, 0.10 mmol, 1.00 equiv) was dissolved in a neutral atmosphere in 2 mL of DCM and the solution was cooled with an ice bath. TFA (1 mL) was added and the reaction agitated for 2 hours at ambient temperature, then concentrated under reduced pressure. The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% of TFA; Gradient of 18% to 31% ACN in 7 minutes then 31% to 100% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm). Compound 1 was obtained with a yield of 25% (23 mg) in the form of a white solid.

LC/MS/UV (Atlantis T3 column, 3 μm, 4.6×100 mm; 35° C.; 1 mL/min, 30% to 60% ACN in water (20 mM ammonium acetate in 6 minutes); ESI (C₄₄H₇₃N₇O₆S, exact masse 827.53) m/z: 829 (MH⁺), 5.84 min (93.7%, 254 nm).

¹H NMR (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.85-7.80 (m, 1H); 7.69-7.66 (m, 1H), 7.40-7.10 (m, 5H), 5.80-5.63 (m, 1H), 4.80-4.65 (m, 2H), 4.22-4.00 (m, 1H), 3.89-0.74 (m, 58H).

Compound 2 (S)-2-((S)-2-(((2-aminopyridin-4-yl)methyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-1-((S)-2-((1R,2R)-3-(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2-methyl-3-oxopropyl)pyrrolidin-1-yl)-3-methoxy-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide, Trifluoroacetic Acid

Compound 2A: tert-butyl (S)-2-((1R,2R)-3-(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2-methyl-3-oxopropyl)pyrrolidine-1-carboxylate

Compound 1D (2.5 g, 8.70 mmol, 1.00 equiv) and (1S,2R)-2-amino-1-phenylpropan-1-ol (1.315 g, 8.70 mmol, 1.00 equiv) were dissolved in an inert atmosphere in DMF (35 mL). The solution was cooled to 0° C. then DEPC (1.39 mL) and TEA (1.82 mL) were added drop-wise. The reaction mixture was agitated 2 hours at 0° C. then 4 hours at ambient temperature. The reaction mixture was diluted with 200 mL of water and extracted three times with 50 mL of EtOAc. The organic phases were combined, washed once with 50 mL of KHSO₄ (1 mol/L), once with 50 mL of NaHCO₃ (sat.), once with 50 mL of NaCl (sat.), then dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 3.6 g (98%) of compound 2A in the form of a yellow solid.

Compound 2B: (2R,3R)—N— ((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)-3-methoxy-2-methyl-3-((S)-pyrrolidin-2-yl)propanamide2,2,2-trifluoroacetate

Compound 2A (2.7 g, 6.42 mmol, 1.00 equiv) was dissolved in an inert atmosphere in DCM (40 mL) then cooled to 0° C. TFA (25 mL) was added and the solution agitated for 2 hours at 0° C. The reaction mixture was concentrated under reduced pressure to yield 4.4 g of compound 2B in the form of a yellow oil.

Compound 2C: (9H-fluoren-9-yl)methyl ((S)-1-(((3R,4S,5S)-1-((S)-2-((1R,2R)-3-(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2-methyl-3-oxopropyl)pyrrolidin-1-yl)-3-methoxy-5-methyl-1-oxoheptan-4-yl) (methyl)amino)-3-methyl-1-oxobutan-2-yl)carbamate

Compounds 2B (4.4 g, 10.13 mmol, 1.00 equiv) and 1W (5.31 g, 10.12 mmol, 1.00 equiv) were dissolved in an inert atmosphere in DCM (45 mL). The solution was cooled to 0° C. then DEPC (1.62 mL) and DIEA (8.4 mL) were added drop-wise. The reation mixture was agitated for 2 hours at 0° C. then at ambient temperature overnight. The reaction mixture was diluted with 100 mL of water and extracted three times with 50 mL of DCM. The organic phases were combined, washed once with 50 mL of KHSO₄ (1 mol/L), once with 50 mL of NaHCO₃ (sat.), once with 50 mL of NaCl (sat.), then dried over sodium sulfate, filtered and concentrated under pressure to yield 3.3 g (39%) of compound 2C in the form of a yellow solid.

Compound 2D: (S)-2-amino-N-((3R,4S,5S)-1-((S)-2-((1R,2R)-3-(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2-methyl-3-oxopropyl)pyrrolidin-1-yl)-3-methoxy-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide

Compound 2C (300 mg, 0.36 mmol, 1.00 eq.) was dissolved in an inert atmosphere in ACN (2 mL) and piperidine (0.5 mL). The solution was left under agitation at ambient temperature overnight then evaporated to dryness under reduced pressure. The residue was purified on a silica column with a mixture of DCM and MeOH (1:100) to yield 150 mg (68%) of compound 2D in the form of a white solid.

Compound 2E: methyl 2-((tert-butoxycarbonyl)amino)isonicotinate

Methyl 2-aminopyridine-4-carboxylate (2 g, 13.14 mmol, 1.00 equiv) was dissolved in tert-butanol (20 mL) after which di-tert-butyl dicarbonate (4.02 g, 18.42 mmol, 1.40 equiv) was added. The reaction mixture was agitated at 60° C. overnight then the reaction was halted through the addition of an aqueous 1M NaHCO₃ solution (50 mL). The solid was recovered by filtration, washed with 50 mL of EtOH then dried in vacuo to yield 2.5 g (75%) of compound 2E in the form of a white solid.

Compound 2F: tert-butyl (4-(hydroxymethyl)pyridin-2-yl)carbamate

Compound 2E (2.5 g, 9.91 mmol, 1.00 equiv) and CaCl₂ (1.65 g) were dissolved in EtOH (30 mL). The solution was cooled to 0° C. then NaBH₄ (1.13 g, 29.87 mmol, 3.01 equiv) was gradually added. The solution was left under agitation overnight at ambient temperature then the reaction was halted with the addition of water (50 mL). The mixture was extracted three times with 20 mL of EtOAc. The organic phases were combined, washed twice with 20 mL of NaCl (sat.) then dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 2.0 g (90%) of compound 2F in the form of a colourless solid.

Compound 2G: tert-butyl (4-formylpyridin-2-yl)carbamate

Compound 2F (2.5 g, 11.15 mmol, 1.00 equiv) was dissolved in DCE (25 mL) then 19.4 g (223.14 mmol, 20.02 equiv) of MnO₂ were added. The mixture was left under agitation overnight at 70° C. then the solids were removed by filtering. The filtrate was evaporated to dryness to yield 1.4 g (57%) of compound 2G in the form of a white solid.

Compound 2H: benzyl (S)-2-(((2-((tert-butoxycarbonyl)amino)pyridin-4-yl)methyl)(methyl)amino)-3-methylbutanoate

Compound 2G (2.3 g, 10.35 mmol, 1.00 equiv) was dissolved in 25 mL of THF in the presence of compound 1ZC (2.93 g, 11.37 mmol, 1.10 equiv), DIEA (5.39 g, 41.71 mmol, 4.03 equiv) and NaBH(OAc)₃ (4.39 g, 20.71 mmol, 2.00 equiv). The reaction mixture was agitated for 6 hours at ambient temperature then neutralised with 60 mL of NaHCO₃ (sat.) and extracted 3 times with 20 mL of AcOEt. The organic phases were combined, washed twice with 20 mL of NaCl (sat.), dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of EtOAc and PE (1:15) to yield 2.7 g (61%) of compound 2H in the form of a white solid.

Compound 2I: (S)-2-(((2-((tert-butoxycarbonyl)amino)pyridin-4-yl)methyl) (methyl)amino)-3-methylbutanoic Acid

Compound 2H (500 mg, 1.17 mmol, 1.00 equiv) was dissolved in 10 mL of AcOEt and 2 mL of methanol in the presence of Pd/C (250 mg), and hydrogenated for 3 hours at ambient temperature and atmospheric pressure. The reaction medium was filtered and concentrated under reduced pressure to yield 254 mg (64%) of compound 2I in the form of a colourless solid

Compound 2J: tert-butyl (4-((3S,6S,9S,10R)-9-(S)-sec-butyl)-10-(2-((S)-2-((1R,2R)-3-(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2-methyl-3-oxopropyl)pyrrolidin-1-yl)-2-oxoethyl)-3,6-diisopropyl-2,8-dimethyl-4,7-dioxo-11-oxa-2,5,8-triazadodecyl)pyridin-2-yl) carbamate

Compound 2J was prepared in similar manner to compound 1ZG from the amine 2D (85.2 mg, 0.14 mmol, 1.50 equiv), the acid 2I (31.7 mg, 0.09 mmol, 1.00 equiv), HATU (42.9 mg, 0.11 mmol, 1.20 equiv) and DIEA (36.7 mg, 0.28 mmol, 3.02 equiv) in DMF (3 mL). After evaporation to dryness, 100 mg of crude product were obtained in the form of a white solid.

Compound 2J (100 mg, 0.11 mmol, 1.00 equiv) was dissolved in 2 mL of DCM and 1 mL of TFA. The reaction was agitated for 1 hour at ambient temperature, then concentrated under reduced pressure. The residue (80 mg) was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm). Compound 2 was obtained with a yield of 6% (6.3 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.8 mL/min, from 10% to 95% ACN in water (0.05% TFA) in 6 minutes); ESI (C₄₅H₇₃N₇O₇, exact mass 823.56) m/z: 824.5 (MH⁺) and 412.9 (M.2H⁺/2, 100%), 3.21 min (99.2%, 210 nm)

¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.81-7.79 (m, 1H); 7.39-7.29 (m, 5H); 6.61-6.59 (m, 2H); 4.84-4.52 (m, 1H); 4.32-4.02 (m, 1H); 3.90-2.98 (m, 10H); 2.90-2.78 (m, 1H); 2.55-0.81 (m, 39H).

Reference Compound 3 methyl ((S)-2-(2R,3R)-3-((S)-1-(3R,4S,5S)-4-((S)—N,3-dimethyl-2-((S)-3-methyl-2-(methyl(pyridin-4-ylmethyl)amino)butanamido)butanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, trifluoroacetic acid

Compound 3A: tert-butyl (S)-2-((1R,2R)-1-methoxy-3-(((S)-1-methoxy-1-oxo-3-phenylpropan-2-yl)amino)-2-methyl-3-oxopropyl)pyrrolidine-1-carboxylate

Compound 1D (3 g, 10.44 mmol, 1.00 equiv) and methyl (S)-2-amino-3-phenylpropanoate (2.25 g, 12.55 mmol, 1.20 equiv) were dissolved in an inert atmosphere in DMF (40 mL). The solution was cooled to 0° C. then DEPC (1.67 mL, 1.05 equiv) and TEA (3.64 mL, 2.50 equiv) were added drop-wise. The reaction mixture was agitated 2 hours at 0° C. then at ambient temperature overnight. The reaction mixture was diluted with 100 mL of water and extracted three times with 50 mL EtOAc. The organic phases were combined, washed once with 100 mL of KHSO₄ (1 mol/L), once with 100 mL of NaHCO₃ (sat.), once with 100 mL of NaCl (sat.), then dried over sodium sulfate, filtered and concentrated under pressure to yield 4 g (85%) of compound 3A in the form of a colourless oil.

Compound 3B: 2,2,2-trifluoroacetate of methyl (S)-2-(2R,3R)-3-methoxy-2-methyl-3-((S)-pyrrolidin-2-yl)propanamido)-3-phenylpropanoate

Compound 3A (5 g, 11.15 mmol, 1.00 equiv) was dissolved in an inert atmosphere in DCM (40 mL). TFA (25 mL) was added and the solution agitated for 2 hours. The reaction mixture was concentrated under reduced pressure to yield 8 g of compound 3B in the form of a yellow oil.

Compound 3C: methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((((9H-fluoren-9-yl)methoxy)carbonyl)amino)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate

Compounds 3B (8.03 g, 17.36 mmol, 1.00 equiv) and 1W (9.1 g, 17.34 mmol, 1.00 equiv) were dissolved in an inert atmosphere in DCM (80 mL). The solution was cooled to 0° C. then DEPC (2.8 mL) and DIEA (12 mL) were added drop-wise. The reaction mixture was agitated for 2 hours at 0° C. then at ambient temperature overnight. The reaction mixture was diluted with 200 mL of water and extracted three times with 50 mL of DCM. The organic phases were combined, washed once with 50 mL of KHSO₄ (1 mol/L), once with 50 mL of NaHCO₃ (sat.), once with 50 mL of NaCl (sat.), then dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 5 g (34%) of compound 3C in the form of a yellow solid.

Compound 3D: methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-amino-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate

Compound 3C (5.5 g, 6.43 mmol, 1.00 equiv) was dissolved in an inert atmosphere in a solution of tetrabutylammonium fluoride (TBAF, 2.61 g, 9.98 mmol, 1.55 quiv) in DMF (100 mL). The solution was agitated at ambient temperature for 2 hours then diluted with 100 mL of water and extracted three times with 50 mL of EtOAc. The organic phases were combined then dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 3.3 g (81%) of compound 3D in the form of a yellow solid.

Compound 3E: benzyl (S)-3-methyl-2-(methyl(pyridin-4-ylmethyl)amino) butanoate

Pyridine-4-carbaldehyde (1 g, 9.34 mmol, 1.00 equiv) was dissolved in 10 mL of 1,2-dichloroethane (DCE) in the presence of compound 1ZC (2.9 g, 11.25 mmol, 1.21 equiv) and titanium isopropoxide (IV) (4.19 mL, 1.40 equiv). The mixture was agitated at ambient temperature for 30 minutes then 2.77 g of NaBH(OAc)₃ (13.07 mmol, 1.40 equiv) were added. The reaction medium was left under agitation overnight then neutralised with 100 mL of water and the mixture extracted 3 times with 50 mL of AcOEt. The organic phases were combined and evaporated to dryness. The residue was purified on a silica column with a mixture of EtOAc and PE (1:20) to yield 1.3 g (45%) of compound 3E in the form of a colourless oil.

Compound 3F: (S)-3-methyl-2-(methyl(pyridin-4-ylmethyl)amino)butanoic acid

Compound 3E (800 mg, 2.56 mmol, 1.00 equiv) was dissolved in 30 mL of AcOEt in the presence of Pd/C (300 mg) and hydrogenated for 3 hours at ambient temperature and atmospheric pressure. The reaction medium was filtered and concentrated under reduced pressure. The residue was purified on a silica column with a mixture of DCM and MeOH (100:1 to 5:1) to yield 100 mg (18%) of compound 3F in the form of a white solid.

Compounds 3D (50 mg, 0.08 mmol, 1.00 equiv) and 3F (26.34 mg, 0.12 mmol, 1.50 equiv) were dissolved in 3 mL of DCM. The solution was cooled to 0° C. then 0.018 mL of DEPC and 0.0392 mL of DIEA were added. The reaction was agitated at 0° C. for 2 hours then at ambient temperature overnight. The reaction medium was concentrated under reduced pressure and the residue (70 mg) was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% of TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 3 was obtained with a yield of 27% (20 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% ACN in water (0.05% TFA) in 8 minutes); ESI (C₄₆H₇₂N₆O₈, exact mass 836.5) m/z: 837.5 (MH⁺) and 419.4 (M.2H⁺/2 (100%)), 7.04 min (90.0%, 210 nm)

¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.76-8.74 (m, 2H); 8.53-8.48 (m, 0.4H, NHCO incomplete exchange); 8.29-8.15 (m, 0.8H, NHCO incomplete exchange); 8.01 (s, 2H), 7.31-7.22 (m, 5H), 4.88-4.68 (m, 3H); 4.31-4.07 (m, 2H); 3.94-2.90 (m, 18H); 2.55-0.86 (m, 38H).

Reference Compound 4 (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)—N,3-dimethyl-2-((S)-3-methyl-2-(methyl(pyridin-4-ylmethyl)amino)butanamido)butanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, trifluoroacetic acid

Compound 3 (100 mg, 0.11 mmol, 1.00 equiv) was dissolved in a mixture of water (5 mL), ACN (5 mL) and piperidine (2.5 mL). The reaction mixture was left under agitation overnight then concentrated under reduced pressure. The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05 TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm), to yield 20 mg (20%) of compound 4 in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% ACN in water (0.05% TFA) in 8 minutes); ESI (C₄₅H₇₀N₆O₈, exact mass 822.5) m/z: 823.5 (MH⁺) and 412.4 (M.2H⁺/2, 100%), 6.84 min (89.1%, 210 nm).

¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.79-8.78 (m, 2H); 8.09 (m, 2H); 7.30-7.21 (m, 5H); 4.80-4.80 (m, 1H), 4.36-0.87 (m, 58H).

Compound 6 methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((3-aminopropyl) (methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, bis trifluoroacetic acid

Compound 6A: methyl (2S)-2-[(2R)-2-[(R)-[(2S)-1-[(3R,4S,5S)-4-[(2S)-2-[(2S)-2-[(3-[[(tert-butoxy)carbonyl]amino]propyl)(methyl)amino]-3-methyl butanamido]-N,3-dimethylbutanamido]-3-methoxy-5-methylheptanoyl]pyrrolidin-2-yl](methoxy)methyl]propanamido]-3-phenylpropanoate

Compound 3D (157.5 mg, 0.25 mmol, 1.00 equiv) was dissolved at 0° C. in an inert atmosphere in 3 mL of DCM in the presence of carboxylic acid 1ZF (78.7 mg, 0.27 mmol, 1.10 equiv), DEPC (46 μl) and DIEA (124 μl). The reaction mixture was agitated 2 hours at low temperature and the cold bath was then removed and agitation continued for 4 hours. It was then concentrated under reduced pressure to yield 200 mg of compound 6A in the form of a crude yellow oil. It was used as such in the following step.

Compound 6A (200 mg, 0.22 mmol, 1.00 equiv) was dissolved in an inert atmosphere at 0° C. in 2 mL of DCM. TFA (1 mL) was added drop-wise and the cold bath removed. The reaction mixture was agitated 1 hour at ambient temperature then concentrated under reduced pressure. The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm), to yield 60 mg (26%, yield in 2 steps) of compound 6 in the form of a white solid.

LC/MS/UV (Zorbax Eclipse Plus C8, 3.5 μm, 4.6×150 mm; 1 m/min, 40° C., 30 to 80% methanol in water (0.1% H₃PO₄) in 18 minutes); ESI (C₄₃H₇₄N₆O₈, exact mass 802.56) m/z: 804 (MH⁺); 11.50 min (91.5%, 210 nm).

¹H NMR (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.52 (d, 0.3H, NHCO incomplete exchange); 8.25 (d, 0.5H, NHCO incomplete exchange); 7.30-7.22 (m, 5H); 4.9-4.6 (m, 3H); 4.2-4.0 (m, 1H); 4.0-0.86 (m, 61H).

Compound 7 (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((3-aminopropyl) (methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl) pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, bis trifluoroacetic acid

Compound 6 (70 mg, 0.08 mmol, 1.00 equiv) was dissolved in a mixture of water (5 mL), ACN (2.5 mL) and piperidine (5 mL). The reaction mixture was left under agitation overnight at ambient temperature, then concentrated under reduced pressure. The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; UV Waters 2489 UV Detector at 254 nm and 220 nm), to yield 14.6 mg (21%) of compound 7 in the form of a white solid.

LC/MS/UV (Ascentis Express C18, 2.7 μm, 4.6×100 mm; 1.5 mL/min, 40° C., 0 to 80% methanol in water (0.05% TFA) in 8 minutes); ESI (C₄₂H₇₂N₆O₈, exact mass 788.54) m/z: 790 (MH⁺), 5.71 min (96.83%, 210 nm).

¹H NMR (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.42 (d, 0.3H, NHCO incomplete exchange); 8.15 (d, 0.2H, NHCO incomplete exchange); 7.31-7.21 (m, 5H); 4.9-4.6 (m, 3H); 4.25-4.0 (m, 1H); 4.0-0.86 (m, 59H).

Compound 8 (S)-2-((S)-2-(((2-aminopyridin-4-yl)methyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide, trifluoroacetic acid

Compound 8A: tert-butyl (4-((3S,6S,9S,10R)-9-((S)-sec-butyl)-3,6-diisopropyl-10-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-2,8-dimethyl-4,7-dioxo-11-oxa-2,5,8-triazadodecyl)pyridin-2-yl) carbamate

Compound 8A was synthesised in the same manner as for compound 2J from the amine 1Y (39 mg, 0.06 mmol, 1.00 equiv), the acid 2I (20 mg, 0.06 mmol, 1.00 equiv), HATU (27 mg, 0.07 mmol, 1.20 equiv) and DIEA (23.2 mg, 0.18 mmol, 3.01 equiv) in DCM (3 mL). The crude product was not purified.

Compound 8: Compound 8 was synthesised in similar manner to compound 2 from the intermediate 8A (100 mg, 0.10 mmol, 1.00 equiv). The crude product (100 mg) was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 18% to 31% ACN in 7 minutes then 31% to 100% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm). Compound 8 was obtained with a yield of 8% (8 mg) in the form of a white solid.

LC/MS/UV (Atlantis T3 column, 3 μm, 4.6×100 mm; 35° C.; 1.8 mL/min, 25% to 80% ACN in water (0.05% TFA) in 7 minutes); ESI (C₄₇H₇₂N₈O₆S, exact mass 876.5) m/z: 877.5 (MH⁺) and 439.5 (M.2H⁺/2, 100%), 4.87 min (95.1%, 254 nm).

¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.83-7.78 (m, 2H); 7.56-7.52 (m, 1H); 7.34-7.17 (m, 5H); 6.64-6.62 (m, 2H); 5.77-5.61 (m, 1H); 4.86-4.68 (m, 2H); 4.25-4.05 (m, 1H); 3.87-2.83 (m, 17H); 2.56-0.84 (m, 37H).

Compound 9 methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-(((2-aminopyridin-4-yl)methyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, trifluoroacetic acid

Compound 9A: methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-(((2-((tert-butoxycarbonyl)amino)pyridin-4-yl)methyl)(methyl)amino)-3-methyl butanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate

Compound 9A was synthesised in the same manner as for compound 3 from the amine 3D (170 mg, 0.27 mmol, 1.00 equiv), the acid 2I (99.7 mg, 0.30 mmol, 1.10 equiv), DEPC (0.049 mL, 1.05 equiv) and DIEA (0.133 mL, 3.00 equiv) in DCM (5 mL). The crude product was purified on a silica column with a mixture of EtOAc and PE (1:1) to yield 200 mg (78%) of compound 9A in the form of a pale yellow solid

Compound 9: Compound 9 was synthesised in the same manner as for compound 2 from the intermediate 9A (200 mg, 0.21 mmol, 1.00 equiv) in DCM (4 mL) and TFA (2 mL). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 9 was obtained with a yield of 10% (20 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₆H₇₃N₇O₈, exact mass 851.6) m/z: 852.5 (MH⁺) and 426.9 (M.2H⁺/2, 100%), 6.92 min (92.7%, 254 nm).

¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.51-8.45 (m, 0.5H, NH incomplete exchange); 8.30-8.24 (m, 0.3H, NH incomplete exchange); 8.17-8.07 (m, 0.8H, NH incomplete exchange); 7.79-7.77 (m, 1H); 7.36-7.18 (m, 5H); 7.21-7.16 (m, 1H); 6.94-6.89 (m, 1H); 4.85-4.65 (m, 3H); 4.20-3.10 (m, 20H); 3.00-2.85 (m, 2H); 2.55-0.80 (m, 36H).

Compound 10 (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-(((2-aminopyridin-4-yl)methyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, trifluoroacetic acid

Compound 10: Compound 9 (100 mg, 0.11 mmol, 1.00 equiv) was dissolved in a mixture of water (5 mL), ACN (5 mL) and piperidine (2.5 mL). The reaction mixture was left under agitation overnight at ambient temperature and then concentrated under reduced pressure. The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm), to yield 32.2 mg (33%) of compound 10 in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₅H₇₁N₇O₆, exact mass 837.5) m/z: 838.5 (MH⁺) and 419.9 (M.2H⁺/2, 100%), 6.81 min (97.7%, 220 nm).

¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.41-8.32 (m, 0.3H, NH incomplete exchange); 8.20-8.07 (m, 0.8H, NH incomplete exchange); 7.82-7.75 (m, 1H); 7.36-7.158 (m, 5H); 7.12-7.03 (m, 1H); 6.94-6.88 (m, 1H); 4.85-4.66 (m, 3H); 4.20-3.10 (m, 16H); 3.00-2.85 (m, 2H); 2.57-0.80 (m, 37H).

Compound 11 (S)—N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethyl-2-((S)-3-methyl-2-(methyl(4-(methylamino)phenethyl)amino) butanamido)butanamide, trifluoroacetic acid

Compound 11A: tert-butyl N-[4-(2-hydroxyethyl)phenyl]carbamate

Di-tert-butyl dicarbonate (16.7 g, 77 mmol, 1.05 eq.) was added to a solution of 2-(4-aminophenyl)ethanol (10 g, 72.9 mmol, 1 eq.) in THF (200 mL), and the reaction stirred overnight at ambient temperature. The mixture was diluted with EtOAc (200 mL), washed with water (200 mL), then HCl 1M (100 mL), then saturated aqueous NaHCO₃ solution (100 mL) then brine (100 mL). The organic phase was dried over MgSO₄ then evaporated to dryness under reduced pressure. The crude product was triturated twice with heptane (150 mL) and dried under vacuum to furnish compound 11A as a white solid (14.7 g, 84%).

Compound 11B: tert-butyl N-[4-(2-oxoethyl)phenyl]carbamate

Compound 11A (2.5 g, 10.5 mmol, 1.00 equiv) was dissolved in 25 mL of DCM then cooled to −78° C. A Dess-Martin Periodinane solution (DMP, 6.71 g, 15.8 mmol, 1.5 equiv) in DCM (10 mL) was added drop-wise. The cold bath was removed and agitation continued for 1 hour at ambient temperature. The reaction was neutralised with 60 mL of a 50/50 mixture of sodium bicarbonate-saturated aqueous solution and Na₂S₂O₃-saturated aqueous solution. The resulting solution was extracted 3 times with 30 mL of EtOAc. The organic phases were combined, washed twice with NaCl-saturated aqueous solution, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified on silica gel (EtOAc/PE 1/15) to yield 1.0 g (40%) of compound 11B in the form of a pale yellow solid.

Compound 11C: benzyl (2S)-2-[[2-(4-[[(tert-butoxy)carbonyl]amino]phenyl) ethyl](methyl)amino]-3-methylbutanoate

Compound 1ZC (3.5 g, 13.6 mmol, 1.1 equiv) was dissolved in THF (30 mL) in the presence of DIEA (6.4 g, 49.7 mmol, 4.0 equiv), aldehyde 11B (2.9 g, 12.3 mmol, 1.0 equiv) and sodium triacetoxyborohydride (5.23 g, 49.7 mmol, 2.0 equiv). The reaction mixture was left under agitation overnight at ambient temperature, then neutralised with 60 mL of sodium bicarbonate-saturated solution. The resulting solution was extracted 3 times with 30 mL EtOAc. The organic phases were combined, washed twice with NaCl-saturated aqueous solution, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified on silica gel (EtOAc/PE 1:20) to yield 3.7 g (68%) of compound 11C in the form of a yellow oil.

Compound 11D: (2S)-2-[[2-(4-[[(tert-butoxy)carbonyl]amino]phenyl)ethyl](methyl)amino]-3-methylbutanoic acid

Compound 11C (2 g, 4.5 mmol, 1 equiv) was dissolved in 10 mL of methanol in the presence of Pd/C (2 g) and hydrogenated for 2 hours at normal temperature and pressure. The reaction medium was filtered and concentrated under reduced pressure to yield 1.2 g (75%) of compound 11D in the form of a yellow oil.

Compound 11E: (2S)-2-[[2-(4-[[(tert-butoxy)carbonyl](methyl)amino]phenyl) ethyl](methyl)amino]-3-methylbutanoic acid

Compound 11D (1.2 g, 3.4 mmol, 1.00 equiv) was dissolved in an inert atmosphere in THF (20 mL). The reaction medium was cooled with an ice bath after which NaH (60% in oil, 549 mg, 13.7 mmol, 4.0 equiv) was added in portions, followed by iodomethane (4.9 g, 34 mmol, 10 equiv). The reaction was left under agitation overnight at ambient temperature, then neutralised with water and washed with 100 mL of EtOAc. The pH of the aqueous solution was adjusted to 6-7 with 1N HCl. This aqueous solution was extracted 3 times with 100 mL of EtOAc. The organic phases were combined, dried over sodium sulfate, filtered and concentrated to yield 800 mg (64%) of compound 11E in the form of a yellow solid.

Compound 11F: tert-butyl N-[4-(2-[[(1S)-1-[[(1S)-1-[[(3R,4S,5S)-3-methoxy-1-[(2S)-2-[(1R,2R)-1-methoxy-2-methyl-2-[[(1S)-2-phenyl-1-(1,3-thiazol-2-yl)ethyl]carbamoyl]ethyl]pyrrolidin-1-yl]-5-methyl-1-oxoheptan-4yl](methyl)carbamoyl]-2-methylpropyl]carbamoyl]-2-methylpropyl](methyl)amino]ethyl)phenyl]-N-methylcarbamate

Compound 1F was prepared in similar manner to compound 6A from the amine 1Y (150 mg, 0.22 mmol, 1.2 equiv) and the acid 11E (70 mg, 0.19 mmol, 1.0 equiv). After purification on silica gel (EtOAc/PE 1:1) 100 mg (52%) of desired product were obtained in the form of a pale yellow solid.

Compound 11 was prepared in the same manner as for compound 1 from the intermediate 11F (100 mg, 0.1 mmol). The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm). Compound 11 was obtained with a yield of 39% (39.7 mg) in the form of a white solid.

LC/MS/UV (Eclipse Plus C8, 3.5 μm, 4.6×150 mm; 1 m/min, 40° C., 50 to 95% methanol in water (0.05% TFA) in 18 minutes); ESI (C₅₀H₇₇N7O₆S, exact mass 903.57) m/z: 904.5 (MH⁺), 7.53 min (93.68%, 254 nm).

¹H NMR (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.84 (d, 0.5H, NHCO incomplete exchange); 8.7-8.5 (m, 0.9H, NHCO incomplete exchange); 7.76-7.73 (m, 1H); 7.55-7.4 (m, 1H); 7.28-7.22 (m, 7H); 7.08-7.05 (m, 2H); 5.51-5.72 (m, 1H); 4.9-4.80 (m, 2H); 4.3-0.7 (m, 60H).

Compound 12 methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)—N,3-dimethyl-2-((S)-3-methyl-2-(methyl(4-(methylamino)phenethyl)amino)butanamido)butanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, trifluoroacetic acid

In the same manner as for the final phases in the synthesis of compound 1, compound 12 was prepared in two steps from the amine 3D (118 mg, 0.19 mmol) and the acid 11E (82 mg, 0.22 mmol). The final residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm). Compound 12 was obtained with a yield of 7% (13.7 mg) in the form of a white solid.

LC/MS/UV (Eclipse Plus C8, 3.5 μm, 4.6×150 mm; 1 m/min, 40° C., 40 to 95% methanol in water (0.05% TFA) in 18 minutes); ESI (C₄₉H₇₈N6O₈, exact mass 878.59) m/z: 879.7 (MH⁺), 10.07 min (90.6%, 254 nm).

¹H:NMR (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.40 (se, 2H); 7.38-7.22 (m, 7H); 4.95-4.7 (m, 3H); 4.2-4.0 (m, 1H); 3.9-0.86 (m, 62H).

Compound 13 (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)—N,3-dimethyl-2-((S)-3-methyl-2-(methyl(4-(methylamino)phenethyl)amino)butanamido)butanamido)-3-methoxy-5-methyl heptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, trifluoroacetic acid

Compound 13 was prepared in the same manner as for compound 7 from compound 12 (100 mg, 0.10 mmol). The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm). Compound 13 was obtained with a yield of 20% (20 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18, 2.7 μm, 4.6×100 mm; 1.5 m/min, 40° C., 10 to 95% methanol in water (0.05% TFA) in 8 minutes); ESI (C₄₈H₇₆N6O₈, exact mass 864.57) m/z: 865.6 (MH⁺), 6.05 min (90.9%, 210 nm).

¹H NMR: (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.32-7.19 (m, 9H); 4.9-4.65 (m, 3H); 4.2-4.0 (m, 1H); 3.9-0.86 (m, 59H).

Compound 14 (S)-2-((S)-2-((3-aminobenzyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide, trifluoroacetic acid

Compound 14A: tert-butyl (3-(hydroxymethyl)phenyl) carbamate

(3-aminophenyl)methanol (3 g, 24.36 mmol, 1.00 equiv) was dissolved in THF (60 mL) after which di-tert-butyl dicarbonate (6.38 g, 29.23 mmol, 1.20 equiv) was then added. The reaction mixture was left under agitation overnight at ambient temperature and the reaction was then diluted by adding 200 mL of water. The product was extracted 3 times with 100 mL of AcOEt and the organic phases were then recombined, dried over sodium sulfate, filtered and concentrated under reduced pressure to yield the crude product (13.85 g of compound 14A) in the form of a yellow oil.

Compound 14B: tert-butyl (3-formylphenyl)carbamate

Compound 14A (13.8 g, 61.81 mmol, 1.00 equiv) was dissolved in DCE (400 mL) and MnO₂ (54 g, 621.14 mmol, 10.05 equiv) was then added. The mixture was left under agitation at ambient temperature for 3 days after which the solids were removed by filtering. The filtrate was evaporated to dryness and the residue was purified on a silica column with a mixture of EtOAc and PE (1:30) to yield 3 g (22%) of compound 14B in the form of a white solid.

Compound 14C: benzyl (S)-2-((3-((tert-butoxycarbonyl)amino)benzyl) (methyl)amino)-3-methylbutanoate

Compound 14B (1 g, 4.52 mmol, 1.00 equiv) was dissolved in 20 mL of THF in the presence of compound 1ZC (1.16 g, 4.50 mmol, 1.00 equiv), DIEA (3 mL) and NaBH(OAc)₃ (1.92 g, 9.06 mmol, 2.01 equiv). The reaction mixture was left under agitation overnight at ambient temperature and then neutralised with 100 mL of water and extracted 3 times with 50 mL of AcOEt. The organic phases were combined, dried over sodium sulfate, filtered and concentrated. The residue was purified on a silica column with a mixture of EtOAc and PE (1:50) to yield 1.9 g (99%) of compound 14C in the form of a white solid.

Compound 14D: (S)-2-((3-((tert-butoxycarbonyl)amino)benzyl) (methyl)amino)-3-methylbutanoic acid

Compound 14C (1 g, 2.34 mmol, 1.00 equiv) was dissolved in 30 mL of AcOEt and 4 mL of methanol in the presence of Pd/C (400 mg) and hydrogenated for 1 hour at ambient temperature and atmospheric pressure. The reaction medium was filtered and concentrated under reduced pressure to yield 680 mg (86%) of compound 14D in the form of a white solid.

Compound 14E: tert-butyl (3-((3S,6S,9S,10R)-9-((S)-sec-butyl)-3,6-diisopropyl-10-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-2,8-dimethyl-4,7-dioxo-11-oxa-2,5,8-triazadodecyl)phenyl) carbamate

Compound 14E was synthesised in the same manner as for compound 3 from the amine 1Y (100 mg, 0.15 mmol, 1.00 equiv), the acid 14D (102.27 mg, 0.30 mmol, 2.00 equiv), DEPC (0.053 mL) and DIEA (0.046 mL) in DCM (3 mL). The crude product (80 mg) was purified on a silica column with a mixture of EtOAc and PE (1:1) to yield 100 mg (67%) of compound 14E in the form of a pale yellow solid.

Compound 14 was synthesised in the same manner as for compound 2 from the intermediate 14E (100 mg, 0.10 mmol, 1.00 equiv). The crude product (80 mg) was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 14 was obtained with a yield of 10% (10 mg) in the form of a white solid.

LC/MS/UV (Eclipse plus C8 column, 3.5 μm, 4.6×150 mm; 40° C.; 1.0 mL/min, 40% to 95% MeOH in water (0.05% TFA) in 18 minutes); ESI (C₄₈H₇₃N₇O₆S, exact mass 875.5) m/z: 876.5 (MH⁺) and 438.9 (M.2H⁺/2, 100%), 11.35 min (95.6%, 210 nm).

¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.92-8.86 (m, 0.4H, NH incomplete exchange); 8.70-8.54 (m, 0.6H, NH incomplete exchange); 7.88-7.78 (m, 1H); 7.60-7.50 (m, 1H); 7.45-6.97 (m, 9H); 5.80-5.65 (m, 1H); 4.85-4.70 (m, 1H); 4.40-0.80 (m, 56H).

Compound 15 methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((3-aminobenzyl) (methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, trifluoroacetic acid

Compound 15A: methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((3-((tert-butoxycarbonyl)amino)benzyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate

Compound 15A was synthesised in the same manner as for compound 3 from the amine 3D (200 mg, 0.32 mmol, 1.00 equiv), the acid 14D (212.6 mg, 0.63 mmol, 2.00 equiv), DEPC (0.1103 mL) and DIEA (0.157 mL, 3.00 equiv) in DCM (5 mL).

The crude product was purified on a silica column with a mixture of EtOAc and PE (1:1) to yield 200 mg (67%) of compound 15A in the form of a yellow solid.

Compound 15 was synthesised in the same manner as for compound 2 from the intermediate 15A (200 mg, 0.21 mmol, 1.00 equiv). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters UV Detector 2545 at 254 nm and 220 nm). Compound 15 was obtained with a yield of 19% (38.6 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₇H₇₄N₆O₈, exact mass 850.5) m/z: 851.5 (MH⁺) and 426.4 (M.2H⁺/2, 100%), 6.61 min (91.1%, 210 nm).

¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.53-7.42 (m, 1H); 7.35-7.18 (m, 8H); 4.88-4.79 (m, 2H); 4.42-4.00 (m, 3H); 3.93-2.71 (m, 22H); 2.61-0.81 (m, 33H).

Compounds 16 to 20

Compounds 16 to 20 were prepared in the same manner as for compound 1, from the amines 1Y and 1ZC and corresponding aldehydes.

The tert-butyl (4-oxobutyl)carbamate, involved in the preparation of compound 16, was prepared as for compound 1ZE in 2 steps from 4,4-diethoxybutan-1-amine.

The tert-butyl-N-methyl-N-(2-oxoethyl)carbamate involved in the preparation of compound 17 was commercial.

The 2-(2-((tert-butyldimethylsilyl)oxy)ethoxy)acetaldehyde, involved in the preparation of compound 18, was prepared in 2 steps as follows:

2-(2-Hydroxyethoxy)ethan-1-ol (7 g, 66 mmol, 9.9 equiv) was dissolved in an inert atmosphere in pyridine (10 mL) in the presence of 4-dimethylaminopyridine (DMAP, 80 mg, 0.65 mmol, 0.1 equiv). The solution was cooled to 0° C. then TBDMSCI (1 g, 6.6 mmol, 1.0 equiv) was added in portions. The reaction mixture was left under agitation overnight at ambient temperature, diluted with 100 mL of EtOAc and successively washed twice with 100 mL of 1N HCl and twice with NaCl-saturated aqueous solution. The organic phase was dried over anhydrous sodium sulphate, filtered and concentrated under reduced pressure to yield 1.3 g (88%) of 2-[2-[(tert-butyldimethylsilyl)oxy]ethoxy]ethan-1-ol in the form of a colourless oil.

The oxalyl chloride (760 mg, 6 mmol, 1.3 equiv) was dissolved in an inert atmosphere in DCM (40 mL) and cooled to −78° C. Dimethylsulfoxide (DMSO, 1.07 g, 13.7 mmol, 3 equiv) diluted in DCM (5 mL) was added drop-wise. After an agitation time of 30 minutes at low temperature, 2-[2-[(tert-butyldimethyl silyl)oxy]ethoxy]ethan-1-ol (1 g, 4.5 mmol, 1.0 equiv) dissolved in 5 mL of DCM was added. Agitation was continued for 1 hour at low temperature before adding TEA (2.78 g, 27 mmol, 6 equiv). The reaction mixture was agitated 15 minutes at −78° C. and overnight at ambient temperature before being neutralised with 100 mL of water. It was then extracted 3 times with 100 mL of DCM. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified on silica gel (EtOAc/PE 1:20) and yielded 0.8 g (80%) of 2-[2-[(tert-butyldimethylsilyl)oxy]ethoxy]acetaldehyde in the form of a colourless oil.

The tert-butyl 4-formylphenyl carbonate involved in the preparation of compound 19 was prepared in a single step as follows: 4-hydroxybenzaldehyde (2.5 g, 20.5 mmol, 1.0 equiv) was dissolved in an inert atmosphere in THF (20 mL) in the presence of 18-crown-6 (0.25 g) and potassium carbonate (5 g). The reaction mixture was cooled to 0° C. and the di-tert-butyl dicarbonate (5.8 g, 26.58 mmol, 1.30 equiv) was then added. Agitation was continued for 1 hour at low temperature after which the reaction was neutralised with 30 mL of water. The resulting solution was extracted three times with 200 mL of EtOAc. The organic phases were combined, dried over anhydrous sodium sulfate filtered and concentrated under reduced pressure. The residue was purified on silica gel (EtOAc/PE 1:10) and yielded 4.2 g (92%) of tert-butyl 4-formylphenyl carbonate in the form of a pale yellow solid.

The 4-nitrobenzaldehyde involved in the preparation of compound 20 was commercial.

The synthesis of compound 18 was completed by deprotection of the silylated alcohol. This was performed as follows: (S)—N—((S)-1-(((3R,4S,5S)-1-((S)-2-((1R,2R)-3-(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2-methyl-3-oxopropyl)pyrrolidin-1-yl)-3-methoxy-5-methyl-1-oxoheptan-4-yl)(methyl)amino)-3-methyl-1-oxobutan-2-yl)-11-isopropyl-2,2,3,3,10-pentamethyl-4,7-dioxa-10-aza-3-siladodecan-12-amide (40 mg, 0.04 mmol, 1.0 equiv) was dissolved in an inert atmosphere in THF (10 mL) in the presence of TBAF (2 mg, 0.09 mmol, 2 equiv) and agitated 4 hours at ambient temperature. The reaction was neutralised with 50 mL of water then extracted three times with 50 mL of EtOAc. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to yield compound 18 in the crude state.

The synthesis of compound 20 was completed by reducing the nitro group. This was performed as follows: (2S)—N-[(3R,4S,5S)-1-[(2S)-2-[(1R,2R)-2-[[(1S,2R)-1-hydroxy-1-phenylpropan-2-yl]carbamoyl]-1-methoxy-2-methylethyl]pyrrolidin-1-yl]-3-methoxy-5-methyl-1-oxoheptan-4-yl]-N,3-dimethyl-2-[(2S)-3-methyl-2-[methyl[(4-nitrophenyl)methyl]amino]butanamido]butanamide (40 mg, 0.05 mmol, 1.0 equiv) was dissolved in 15 mL of ethanol. Dihydrated tin chloride (II) (317 mg, 1.4 mmol, 30 equiv) was added and the solution left under agitation for 3 days at ambient temperature. The reaction was neutralised with 50 mL of water, then extracted three times with 50 mL of EtOAc. The organic phases were combined, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure to yield compound 20 in the crude state.

N^(o) Name x R Purity* Quantity 16 (S)-2-((S)-2-((4-aminobutyl)(methyl)amino-3-methylbutanamido)-N-((3R,4S,5S)- 3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol- 2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethyl- butanamide, bis trifluoroacetic acid 2

94.9% 11.5 mg 17 (S)-N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)- 2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan- 4-yl)-N,3-dimethyl-2-((S)-3-methyl-2-(methyl(2-(methylamino)ethyl)amino) butanamido)butanamide, bis trifluoroacetic acid 2

99.6% 65.5 mg 18 (S)-2-((S)-2-((2-(2-hydroxyethoxy)ethyl)(methyl)amino)-3-methylbutanamido)-N- ((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2- phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4- yl)-N,3-dimethylbutanamide, trifluoroacetic acid 1

94.5% 46.4 mg 19 (S)-2-((S)-2-((4-hydroxybenzyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)- 3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol- 2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3- dimethylbutanamide, trifluoroacetic acid 1

93.2% 21.6 mg 20 (S)-2-((S)-2-((4-aminobenzyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-3- methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phnyl-1-(thiazol-2- yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3- dimethylbutanamide, trifluoroacetic acid 1

96.7% 21.1 mg *The compounds were purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19 × 150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm), to give the corresponding TFA salts in the form of white solids.

Characterization of the end products: Compound 16 LC/MS/UV (Eclipse Plus C8, 3.5 μm, 4.6×150 mm; 1 mL/min, 40° C., 5 to 95% methanol in water (0.05% TFA) in 18 minutes); ESI: (C₄₅H₇₅N₇O₆S, exact mass 841.55) m/z 842.5 (MH⁺), 421.9 (100%, (M.2H⁺)/2); UV: 14.02 min (94.9%, 210 nm). ¹H NMR (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.55-8.2 (m, 0.8H, NHCO incomplete exchange); 8.0 (0.55H, NHCO incomplete exchange); 7.70 (d, 1H); 7.44 (d, 1H); 7.21-7.15 (m, 5H); 5.65-5.45 (m, 1H); 4.8-4.5 (m, 2H); 4.15-3.9 (m, 2H); 3.8-0.6 (m, 59H). Compound 17 LC/MS/UV ESI: (C₄₄H₇₃N₇O₆S, exact mass 827.53) m/z 828 (MH⁺), 415 [100%, (M.2H⁺)/2]; UV: RT=6.72 min (99.6%, 254 nm)¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.82-7.80 (m, 1H); 7.56-7.54 (m, 1H); 7.35-7.20 (m, 5H); 5.8-5.55 (m, 1H); 4.85-4.6 (m, 1H); 4.25-4.05 (m, 1H); 3.95-0.8 (m, 60H). Compound 18 LC/MS/UV (Atlantis T3, 3 μm, 4.6×100 mm; 1.2 mL/min, 40° C., 5 to 95% methanol in water (0.05% TFA) in 7 minutes) i; ESI: (C₄₅H₇₄N6O₈S, exact mass 858.53) m/z 859 (MH⁺), 881 (MNa⁺), 430 (100%, (M.2H⁺)/2); UV: 4.85 min (96.8%, 220 nm). ¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.75-8.55 (m, 0.5H, NHCO incomplete exchange); 7.85-7.80 (m, 1H); 7.6-7.5 (m, 1H); 7.40-7.15 (m, 5H); 5.8-5.6 (m, 1H); 4.8-4.55 (m, 2H); 4.15-4.0 (m, 1H); 4.0-0.8 (m, 60H). Compound 19 LC/MS/UV ESI: (C₄₈H₇₂N₆O₇S, exact mass 876.52) m/z 877 (MH⁺), 439 [100%, (M.2H⁺)/2]; UV: RT=1.76 min (93.2%, 220 nm). Compound 20 ¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.85-7.80 (m, 1H); 7.6-7.5 (m, 1H); 7.4-7.15 (m, 5H); 7.1-7.05 (m, 2H); 6.73-6.70 (m, 2H); 5.8-5.55 (m, 1H); 5.0-4.7 (m, 2H); 4.25-4.05 (m, 1H); 4.0-0.8 (m, 54H). LC/MS/UV ESI: (C₄₈H₇₃N₇O₇S, exact mass 875.53) m/z 876 (MH⁺), 439 [75%, (M.2H⁺)/2]; UV: RT=4.83 min (96.8%, 254 nm).

¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.85-7.80 (m, 1H); 7.6-7.5 (m, 1H); 7.4-7.1 (m, 7H); 6.76-6.72 (m, 2H); 5.8-5.55 (m, 1H); 4.9-4.65 (m, 2H); 4.25-4.05 (m, 1H); 4.0-0.8 (m, 54H).

Compounds 21 to 24

Compounds 21 to 24 were prepared in the same manner as for compounds 17 to 20, replacing the amine 1Y by the amine 2D.

N^(o) Name x R Purity* Quantity 21 (S)-N-((3R,4S,5S)-1-((S)-2-((1R,2R)-3-(((1S,2R)-1- hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2- methyl-3-oxopropyl)pyrrolidin-1-yl)-3-methoxy-5- methyl-1-oxoheptan-4-yl)-N,3-dimethyl-2-((S)-3- 2

97.5% 24.4 mg methyl-2-(methyl(2-(methylamino)ethyl)amino) butanamido)butanamide, bis trifluoroacetic acid 22 (S)-N-((3R,4S,5S)-1-((S)-2-((1R,2R)-3-(((1S,2R)-1- hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy- 2-methyl-3-oxopropyl)pyrrolidin-1-yl)-3-methoxy- 5-methyl-1-oxoheptan-4-yl)-2-((S)-2-((2-(2- 1

95.5% 26.1 mg hydroxyethoxy)ethyl)(methyl)amino)-3-methyl- butanamido)-N,3-dimethylbutanamide, trifluoroacetic acid 23 (S)-N-((3R,4S,5S)-1-((S)-2-((1R,2R)-3-(((1S,2R)-1- hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2- methyl-3-oxopropyl)pyrrolidin-1-yl)-3-methoxy-5- methyl-1-oxoheptan-4-yl)-2-((S)-2-((4-hydroxy- benzyl)(methyl)amino)-3-methylbutanamido)-N,3- dimethylbutanamide, trifluoroacetic acid 1

98.5%  5.8 mg 24 (S)-2-((S)-2-((4-aminobenzyl)(methyl)amino)-3- methylbutanamido)-N-((3R,4S,5S)-1-((S)-2-((1R,2R)- 3-(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)- 1-methoxy-2-methyl-3-oxopropyl)pyrrolidin-1-yl)-3- methoxy-5-methyl-1-oxoheptan-4-yl)-N,3- dimethylbutanamide, trifluoroacetic acid 1

99.1%  6.9 mg *The compounds were purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19 × 150 mm; Eluting phase: water/ACN buffered with 0.5% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm), to give the corresponding TFA salts in the form of white solids.

Characterization of the end products: Compound 21 LC/MS/UV (ESI) (C₄₂H₇₄N₆O₇, exact mass 774.56) m/z 775 (MH⁺), 797 (MNa⁺), 388 (100%, (M.2H⁺)/2); UV: 3.14 min (97.6%, 215 nm). ¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.05-7.7 (in, 0.81H, NHCO incomplete exchange); 7.45-7.15 (in, 5H); 4.9-4.45 (m, 2H); 4.35-4.00 (m, 2H); 3.95-0.8 (m, 61H). Compound 22 LC/MS/UV (ESI) (C₄₃H₇₅N₅O₉, exact mass 805.56) m/z 806 (MH⁺), 828 (MNa⁺), 404 (100%, (M.2H⁺)/2); UV: 4.47 min (95.6%, 215 nm). ¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.1-7.7 (m, 0.4H, NHCO incomplete exchange); 7.45-7.15 (m, 5H); 4.9-4.5 (m, 3H); 4.4-4.05 (m, 2H); 4.05-0.8 (m, 61H). Compound 23 LC/MS/UV (ESI) (C₄₆H₇₃N₅O₈, exact mass 823.55) m/z 824 (MH⁺), 846 (MNa⁺), 413 (100%, (M.2H⁺)/2); UV: 4.76 min (98.5%, 215 nm). ¹H NMR (400 MHz, CDCl₃, ppm): δ (Presence of rotamers) 7.5-7.2 (m, 5H); 7.9-7.75 (m, 2H); 5.5-5.3 (m, 1H); 4.9-4.6 (m, 2H); 4.55-4.15 (m, 4H); 4.0-0.8 (m, 55H). Compound 24 LC/MS/UV (ESI) (C₄₆H₇₄N₆O₇, exact mass 822.56) m/z 823 (MH⁺), 845 (MNa⁺), 861 (MK⁺); UV: 3.68 min (99.15%, 254 nm). ¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.0-7.7 (m, 0.5H, NHCO incomplete exchange); 7.5-7.0 (m, 7H); 6.75-6.65 (m, 2H); 4.85-4.5 (m, 2H); 4.4-4.05 (m, 2H); 4.0-0.8 (m, 56H).

Compound 26 (S)-2-((S)-2-((2-aminoethyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide, bis trifluoroacetic acid

Compound 26A: benzyl (S)-2-((2-((tert-butoxycarbonyl)amino)ethyl)(methyl)amino)-3-methylbutanoate

Compound 26A was prepared in the same manner as for compound 2H from the amine 1ZC (1.3 g, 5.04 mmol, 1.00 equiv), tert-butyl (2-oxoethyl)carbamate (800 mg, 5.03 mmol, 1.00 equiv), DIEA (3.52 g, 27.24 mmol, 5.42 equiv) and NaBH(OAc)₃ (2.25 g, 10.62 mmol, 2.11 equiv) in THF (25 mL). The mixture was left under agitation overnight and neutralised with 50 mL of water. The residue was purified on a silica column with a mixture of EtOAc and PE (10:1) to yield 0.6 g (33%) of compound 26A in the form of a colourless oil.

Compound 26B: (S)-2-((2-((tert-butoxycarbonyl)amino)ethyl)(methyl)amino)-3-methylbutanoic acid

Compound 26A (600 mg, 1.65 mmol, 1.00 equiv) was dissolved in 40 mL of THF in the presence of Pd/C (300 mg) and hydrogenated for 1 hour at ambient temperature and atmospheric pressure. The reaction medium was filtered and concentrated under reduced pressure. The residue was purified on a silica column with a mixture of EtOAc and MeOH to yield 0.4 g (89%) of compound 26B in the form of a colourless oil.

Compound 26C: tert-butyl ((3R,4S,7S,10S)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2-oxa-5,8,11-triazatridecan-13-yl) carbamate

Compound 26C was prepared in the same manner as for compound 3 from the amine 1Y (70 mg, 0.11 mmol, 1.00 equiv), the acid 26B (58.4 mg, 0.21 mmol, 2.00 equiv), DEPC (0.032 mL) and DIEA (0.053 mL) in DCM (3 mL). After evaporation to dryness, compound 26C was obtained in the form of a yellow oil (100 mg).

Compound 26: Compound 26 was synthesised in the same manner as for compound 2 from the intermediate 26C (100 mg, 0.11 mmol, 1.00 equiv) in DCM (3 mL) and TFA (1.5 mL). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 45% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 26 was obtained with a yield of 38% (38.1 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.0 mL/min, 5% to 95% MeOH in water (0.05% TFA) on 18 minutes); ESI (C₄₃H₇₁N₇O₆S, exact mass 813.52) m/z: 814.5 (MH⁺) and 407.9 (M.2H⁺/2, 100%), 15.78 min (91.2%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.90-8.82 (m, 0.5 H, NH incomplete exchange); 8.71-8.65 (m, 0.3H, NH incomplete exchange); (7.85-7.77 (m, 1H); 7.60-7.49 (m, 1H); 7.37-7.15 (m, 5H); 5.78-5.55 (m, 1H); 4.82-4.62 (m, 1.6H); 4.32-3.83 (m, 3.6H); 3.75-3.35 (m, 7.4H); 3.30-2.60 (m, 13H); 2.58-0.80 (m, 42H).

Compound 27 methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-hydroxyphenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, trifluoroacetic acid

Compound 27: Compound 27 was prepared in the same manner as for compound 3 from the amine 3D (70 mg, 0.11 mmol, 1.00 equiv), the acid 49C (55.5 mg, 0.22 mmol, 2.00 equiv), DEPC (0.034 mL, 2.00 equiv) and DIEA (0.055 mL, 3.00 equiv) in DCM (3 mL). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 45% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 27 was obtained with a yield of 3% (2.9 mg) in the form of a white solid.

LC/MS/UV (Eclipse Plus C8 column, 3.5 μm, 4.6×150 mm; 40° C.; 1.5 mL/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₈H₇₅N₅O₉, exact mass 866.56) m/z: 866.5 (MH⁺) and 433.9 (M.2H⁺/2, 100%), 6.61 min (89.1%, 210 nm).

¹H NMR (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.70-8.49 (m, 0.9 H, NH/OH incomplete exchange); 8.30-8.22 (m, 0.3H, NH incomplete exchange); 7.36-7.02 (m, 7H); 6.86-6.62 (m, 2H); 4.82-4.69 (m, 2H); 4.20-4.03 (m, 1H); 3.91-3.33 (m, 12H); 3.30-2.90 (m, 17H); 2.55-0.80 (m, 35H).

Compound 28 (S)-2-((S)-2-((3-aminobenzyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-1-((S)-2-((1R,2R)-3-(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2-methyl-3-oxopropyl)pyrrolidin-1-yl)-3-methoxy-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide, trifluoroacetic acid

Compound 28A: tert-butyl (3-((3S,6S,9S,10R)-9-((S)-sec-butyl)-10-(2-((S)-2-((1R,2R)-3-(((1S,2R)-1-hydroxy-1-phenylpropan-2-yl)amino)-1-methoxy-2-methyl-3-oxopropyl)pyrrolidin-1-yl)-2-oxoethyl)-3,6-diisopropyl-2,8-dimethyl-4,7-dioxo-11-oxa-2,5,8-triazadodecyl)phenyl)carbamate

Compound 28A was prepared in the same manner as for compound 3 from the amine 2D (100 mg, 0.17 mmol, 1.00 equiv), the acid 14D (111.25 mg, 0.33 mmol, 2.00 equiv), DEPC (0.058 mL) and DIEA (0.05 mL) in DCM (3 mL). The residue was purified on a silica column with a mixture of EtOAc and hexane (1:1) to yield 100 mg (66%) of compound 28A in the form of a white solid.

Compound 28: Compound 28 was synthesised in the same manner as for compound 2 from the intermediate 28A (100 mg, 0.11 mmol, 1.00 equiv). The crude product (80 mg) was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 28 was obtained with a yield of 20% (20 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₆H₇₄N₆O₇, exact mass 822.56) m/z: 823.5 (MH⁺) and 412.4 (M.2H⁺/2, 100%), 12.45 min (87.2%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.47-7.20 (m, 5H); 7.10-7.01 (m, 1H); 6.80-6.56 (m, 3H); 4.82-4.52 (m, 3H); 4.33-4.03 (m, 2H); 3.91-3.82 (m, 0.5H); 3.75-3.35 (m, 9.5H); 3.28-3.10 (m, 2H); 2.79-2.90 (m, 1H); 2.60-2.40 (m, 2H); 2.30-0.80 (m, 40H).

Compound 29 (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((3-aminobenzyl) (methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, trifluoroacetic acid

Compound 15 (100 mg, 0.10 mmol, 1.00 equiv) was dissolved in a mixture of water (5 mL), ACN (5 mL) and piperidine (2.5 mL). The reaction mixture was left under agitation overnight at ambient temperature and then concentrated under reduced pressure. The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm), to yield 20 mg (20%) of compound 29 in the form of a white solid.

LC/MS/UV (Eclipse Plus C8 column, 3.5 μm, 4.6×150 mm; 40° C.; 1.0 m/min, 40% to 95% MeOH in water (0.05% TFA) in 18 minutes); ESI (C₄₆H₇₂N₆O₈, exact mass 836.54) m/z: 837.5 (MH⁺) and 419.4 (M.2H⁺/2, 100%), 10.61 min (92.5%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.38-7.15 (m, 6H); 7.00-6.99 (m, 3H); 4.85-4.68 (m, 2H); 4.37-3.38 (m, 11H); 3.31-2.70 (m, 8H); 2.60-0.82 (m, 35H).

Compound 30 methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-aminobutyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, bis trifluoroacetic acid

Compound 30 was prepared in the same manner as for compound 16, from the amine 3D and the corresponding carboxylic acid.

LC/MS/UV (Ascentis Express C18, 2.7 μm, 4.6×100 mm; 1.5 m/min, 40° C., 10 to 95% methanol in water (0.05% TFA) in 15 minutes); ESI (C44H₇₆N6O₈, exact mass 816.57) m/z: 817.6 (MH⁺), 409.4 (M.2H⁺/2); 12.0 min (90%, 210 nm).

¹H NMR (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.7-8.2 (m, 1H, NHCOs, incomplete exchange); 7.4-7.1 (m, 5H); 4.95-4.7 (m, 3H); 4.2-4.0 (m, 1H); 3.9-0.8 (m, 63H).

Compound 31 (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-aminobutyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, bis trifluoroacetic acid

Compound 31 was prepared in the same manner as for compound 4, from the methyl ester 30.

LC/MS/UV (Ascentis Express C18, 2.7 μm, 4.6×100 mm; 1.5 m/min, 40° C., 10 to 95% methanol in water (0.05% TFA) in 18 minutes); ESI (C₄₃H₇₄N₆O₈, exact mass 802.56) m/z: 803.6 (MH⁺), 402.4 (M.2H⁺/2); 13.68 min (98.9%, 210 nm).

¹H NMR (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.4-7.1 (m, 5H); 4.95-4.7 (m, 3H); 4.2-4.0 (m, 1H); 3.9-0.8 (m, 61H).

Compound 32 (S)—N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethyl-2-((S)-3-methyl-2-(methyl(3-(methylamino)propyl)amino) butanamido)butanamide, bis trifluoroacetic acid

Compound 32A: tert-butyl (3,3-diethoxypropyl)(methyl)carbamate

Compound 1ZD (247 mg, 1 mmol, 1.00 equiv) was dissolved in an inert atmosphere in 30 mL of a 1:1 mixture of THF and DMF. The reaction medium was cooled over an ice bath after which the NaH (60% in oil, 60 mg, 1.5 equiv) was added in portions, followed by the Mel (0.28 mL) drop-wise. The reaction was left under agitation for 2 days at ambient temperature, then neutralised with 5 mL of NH₄C1-saturated aqueous solution and extracted twice with 15 mL of EtOAc. The organic phases were combined, dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 200 mg (77%) of compound 32A in the form of a yellow solid.

Compound 32B: (S)-2-((3-((tert-butoxycarbonyl)(methyl)amino)propyl) (methyl)amino)-3-methylbutanoic acid

Compound 32B was prepared following the same protocol described for the preparation of compound 1ZF, replacing compound 1ZD by compound 32A.

Compound 32: Compound 32 was prepared in two steps, following the same protocol described for the preparation of compound 1, from the amine 1Y and the carboxylic acid 32B.

LC/MS/UV (Zorbax SB-Aq, 1.8 μm, 4.6×100 mm, 40° C., 10 to 95% methanol in water (0.05% TFA) in 13 minutes); ESI (C₄₅H₇₅N7O₆S, exact mass 842.19) m/z: 843 (MH⁺), 421.9 (M.2H⁺/2); 11.91 min (88%, 210 nm).

¹H NMR: (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.5-9.0 (m, 0.5H, incomplete exchange NHCOs), 7.85-7.80 (m, 1H); 7.60-7.50 (m, 1H), 7.35-7.15 (m, 5H), 5.80-5.63 (m, 1H), 4.80-4.65 (m, 2H), 4.30-4.00 (m, 1H), 3.95-0.80 (m, 61H).

Compounds 33 and 34

Compounds 33 and 34 were prepared in the same manner as for compounds 6 and 7, replacing the carboxylic acid 1ZF by compound 32B.

N° Name R Purity* Quantity 33 methyl (S)-2-((2R,3R)-3-((S)-1- Me 95% 32 mg ((7S,10S,13S,14R)-13-((S)-sec-butyl)-7,10- diisopropyl-14-methoxy-6,12-dimethyl-8,11- dioxo-2,6,9,12-tetraazahexadecan-16- oyl)pyrrolidin-2-yl)-3-methoxy-2- methylpropanamido)-3-phenylpropanoate, bis trifluoroacetic acid 34 (S)-2-((2R,3R)-3-((S)-1-((7S,10S,13S,14R)- H 98% 18 mg 13-((S)-sec-butyl)-7,10-diisopropyl-14- methoxy-6,12-dimethyl-8,11-dioxo-2,6,9,12- tetraazahexadecan-16-oyl)pyrrolidin-2yl)-3- methoxy-2-methylpropanamido)-3- phenylpropanoic acid, bis trifluoroacetic acid *The compounds were purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 1.9 × 150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm), to yield the corresponding TFA salts in the form of white solids.

Characterization of the end products: Compound 33 LC/MS/UV (ESI) (C₄₄H₇₆N₆O₈, exact mass 816.57) m/z 817.6 (MH⁺), 409.4 (M.2H⁺/2); UV: 5.94 min (95%, 210 nm). ¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) δ 8.6-8.2 (m, 0.8H, NHCO incomplete exchange) 7.30-7.22 (m, 5H), 4.80 (m, 2H), 4.23-0.86 (m, 66H). Compound 34 LC/MS/UV (ESI) (C₄₃H₇₄N₆O₈, exact mass 802.56) m/z 803.6 (MH⁺), 402.4 (M.2H⁺/2); UV: 5.94 min (97.5%, 210 nm). ¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) δ 7.30-7.20 (m, 5H), 4.80 (m, 2H), 4.25-0.86 (m, 63H).

Compound 35 (S)-2-((S)-2-((2-(2-aminoethoxy)ethyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide, bis trifluoroacetic acid

Compound 35A: tert-butyl (2-(2-hydroxyethoxy)ethyl)carbamate

2-(2-aminoethoxy)ethanol (5 g, 47.56 mmol, 1.00 equiv) was dissolved in THF (100 mL) at 0° C. and sodium hydroxide (2 g, 50.00 mmol, 1.05 equiv) was then added (solution in 25 mL of water). A solution of di-tert-butyl dicarbonate (10.38 g, 47.56 mmol, 1.00 equiv) in THF (20 mL) was added drop-wise and the reaction was then left under agitation overnight at ambient temperature. The reaction was diluted by adding 50 mL of water and the product was extracted with 3 times 75 mL of AcOEt. The organic phases were combined, washed once with 100 mL of NaCl (sat.), then dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 9 g (92%) of compound 35A in the form of a yellow oil.

Compound 35B: tert-butyl (2-(2-oxoethoxy)ethyl)carbamate

A solution of DMSO (3.46 mL, 5.00 equiv) in DCM (20 mL) was added drop-wise to a solution of oxalyl chloride (1.9 mL, 2.30 equiv) in DCM (20 mL) at −78° C. under nitrogen. After the addition (30 min), the solution was agitated for 30 minutes and a solution of compound 35A (2 g, 9.74 mmol, 1.00 equiv) in 20 mL DCM was then added. After the addition of TEA (12.2 mL), the reaction was agitated at −78° C. for 30 minutes and then at ambient temperature overnight. The reaction was diluted by adding 100 mL of water and the product was extracted 3 times with 50 mL of AcOEt. The organic phases were combined, dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 1.9 g of compound 35B in the form of a yellow oil.

Compound 35C: benzyl (S)-12-isopropyl-2,2,11-trimethyl-4-oxo-3,8-dioxa-5,11-diazatridecan-13-oate

Compound 35C was synthesised in the same manner as for compound 14C from the amine 1ZC (2.4 g, 9.31 mmol, 1.00 equiv), the aldehyde 35B (1.9 g, 9.35 mmol, 1.00 equiv), NaBH(OAc)₃ (3.96 g, 18.68 mmol, 2.00 equiv) and DIEA (6.2 mL) in THF (40 mL). The reaction mixture was neutralised with 200 mL of water and extracted 3 times with 100 mL of AcOEt. The organic phases were combined, dried over sodium sulfate, filtered and concentrated to yield 2.3 g of compound 35C in the form of a yellow oil.

Compound 35D: (S)-12-isopropyl-2,2,11-trimethyl-4-oxo-3,8-dioxa-5,11-diazatridecan-13-oic acid

Compound 35C (200 mg, 0.49 mmol, 1.00 equiv) was dissolved in 10 mL of EtOH in the presence of Pd/C (200 mg) and hydrogenated overnight. The reaction medium was filtered and concentrated under reduced pressure to yield 150 mg (96%) of compound 35D in the form of a white solid.

Compound 35E: tert-butyl ((3R,4S,7S,10S)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2,14-dioxa-5,8,11-triazahexadecan-16-yl) carbamate

Compound 35E was synthesised in the same manner as for compound 3 from the amine 1Y (70 mg, 0.11 mmol, 1.00equiv), the acid 35D (40.6 mg, 0.13 mmol, 1.20 equiv), DEPC (0.0324 mL) and DIEA (0.0527 mL) in DCM (3 mL). The crude product (100 mg, 98%) was isolated in the form of a yellow oil and subsequently used as such.

Compound 35: Compound 35 was synthesised in the same manner as for compound 2 from the intermediate 35E (100 mg, 0.10 mmol, 1.00 equiv). The crude product was purified by preparative HPLC (Pre-HPLC-010), SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 35 was obtained with a yield of 23% (22.9 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₅H₇₅N7O₇S, exact mass 857.54) m/z: 858.5 (MH⁺) and 429.9 (M.2H⁺/2, 100%), 5.89 min (89.7%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) δ 8.9-8.5 (m, 0.5H, NHCO incomplete exchange), 7.8-7.7 (m, 1H), 7.55-7.45 (m, 1H), 7.35-7.1 (m, 5H), 5.45-5.5 (m, 1H), 4.9-4.6 (m, 1H), 4.3-0.75 (m, 62H).

Compound 36 methyl (S)-2-((2R,3R)-3-((S)-1-((7S,10S,13S,14R)-1-amino-13-((S)-sec-butyl)-7,10-diisopropyl-14-methoxy-6,12-dimethyl-8,11-dioxo-3-oxa-6,9,12-triazahexadecan-16-oyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, bis trifluoroacetic acid

Compound 36A: methyl (S)-2-((2R,3R)-3-((S)-1-((12S,15S,18S,19R)-18-((S)-sec-butyl)-12,15-diisopropyl-19-methoxy-2,2,11,17-tetramethyl-4,13,16-trioxo-3,8-dioxa-5,11,14,17-tetraazahenicosan-21-oyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate

Compound 36A was synthesised in the same manner as for compound 3 from the amine 3D (50 mg, 0.08 mmol, 1.00 equiv), the acid 35D (25 mg, 0.11 mmol, 1.48 equiv), DEPC (0.0337 mL) and DIEA (0.0548 mL) in DCM (3 mL). The crude product (100 mg) was isolated in the form of a yellow oil and subsequently used as such.

Compound 36: Compound 36 was synthesised in the same manner as for compound 2 from the intermediate 36A (100 mg, 0.11 mmol, 1.00 equiv). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 36 was obtained with a yield of 13% (12.7 mg) in the form of a white solid.

LC/MS/UV (Agilent ZORBAX SB-Aq column, 1.8 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 2% MeOH in water (0.05% TFA) for 1 minute then 2% to 95% MeOH in water in 13 minutes, then 95% MeOH in water for 2 minutes); ESI (C44H₇₆N6O₉, exact mass 832.57) m/z: 833.5 (MH⁺) and 417.4 (M.2H⁺/2, 100%), 11.58 min (98.5%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.1-8.5 (m, 0.8H, NHCO incomplete exchange), 7.30-7.1 (m, 5H), 4.9-4.6 (m, 3H), 4.2-0.8 (m, 64H).

Compound 37 (S)-2-((2R,3R)-3-((S)-1-((7S,10S,13S,14R)-1-amino-13-((S)-sec-butyl)-7,10-diisopropyl-14-methoxy-6,12-dimethyl-8,11-dioxo-3-oxa-6,9,12-triazahexadecan-16-oyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, bis trifluoroacetic acid

Compound 37 was prepared in the same manner as for compound 4, from compound 36 (100 mg, 0.11 mmol, 1.00 equiv). The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, Atlantis Prep OBD T3 column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm), to yield 18.4 mg (19%) of compound 37 in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₃H₇₄N₆O₉, exact mass 818.6) m/z: 819.6 (MH⁺) and 410.4 (M.2H⁺/2, 100%), 5.48 min (96.7%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.35-7.2 (m, 5H), 5.0-4.65 (m, 3H), 4.3-0.8 (m, 61H).

Compound 38 methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((2-aminoethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, bis trifluoroacetic acid

Compound 38A: methyl (S)-2-((2R,3R)-3-((S)-1-((9S,12S,15S,16R)-15-((S)-sec-butyl)-9,12-diisopropyl-16-methoxy-2,2,8,14-tetramethyl-4,10,13-trioxo-3-oxa-5,8,11,14-tetraazaoctadecan-18-oyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate

Compound 38A was synthesised in the same manner as for compound 3 from the amine 3D (70 mg, 0.11 mmol, 1.00 equiv), the acid 26B (60.7 mg, 0.22 mmol, 2.00 equiv), DEPC (0.0337 mL) and DIEA (0.0548 mL) in DCM (3 mL). The crude product (100 mg) was isolated in the form of a yellow oil.

Compound 38: Compound 38 was synthesised in the same manner as for compound 2 from the intermediate 38A (100 mg, 0.11 mmol, 1.00 equiv). The crude product was purified by preparative HPLCPre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 38 was obtained with a yield of 10% (10.3 mg) in the form of a white solid.

LC/MS/UV (Agilent ZORBAX SB-Aq column, 1.8 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 2% MeOH in water (0.05% TFA) for 1 minute then 2% to 95% MeOH in water in 13 minutes then 95% MeOH in water for 2 minutes); ESI (C₄₂H₇₂N₆O₈, exact mass 788.5) m/z: 789.5 (MH⁺) and 395.4 (M.2H⁺/2, 100%), 12.97 min (91.0%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.30-7.1 (m, 5H), 4.9-4.6 (m, 3H), 4.2-0.8 (m, 60H).

Compound 39 (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((2-aminoethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, bis trifluoroacetic acid

Compound 39 was prepared in the same manner as for compound 4, from compound 38 (100 mg, 0.11 mmol, 1.00 equiv). The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm), to yield 8.2 mg (8%) of compound 39 in the form of a white solid.

LC/MS/UV (Eclipse Plus C18 column, 3.5 μm, 4.6×150 mm; 40° C.; 1.5 mL/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₁H₇₀N₆O₈, exact mass 774.5) m/z: 775.5 (MH⁺) and 388.4 (M.2H⁺/2, 100%), 6.47 min (93.6%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.35-7.15 (m, 5H), 4.9-4.6 (m, 3H), 4.2-0.8 (m, 57H).

Compound 40 (S)—N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethyl-2-((S)-3-methyl-2-(methyl(4-(methylamino)butyl)amino)butanamido)butanamide, bis trifluoroacetic acid

Compound 40A: tert-butyl (4,4-diethoxybutyl)(methyl)carbamate

Compound 40A was prepared in the same manner as for compound 11E, from tert-butyl(4,4-diethoxybutyl)(methyl)carbamate (5.5 g, 19.97 mmol, 1.00 equiv), NaH (60% in oil, 3.2 g, 80.00 mmol, 4.01 equiv) and iodomethane (14 mL) in THF/DMF (40/20 mL). The reaction was neutralised with 50 mL of NH₄Cl(aq). Compound 40A was isolated in the form of a yellow oil, 5.5 g (95%).

Compound 40B: tert-butyl methyl(4-oxobutyl)carbamate

Compound 40A (3 g, 10.89 mmol, 1.00 equiv) was dissolved in a mixture of AcOH and water (15/4 mL) and the solution was left under agitation overnight. The pH was brought to 7-8 with NaHCO₃-saturated aqueous solution and then extracted twice with 50 mL of EtOAc. The organic phases were combined, washed twice with 50 mL of NaCl-saturated aqueous solution, dried over anhydrous sodium sulfate, filtered and concentrated under reduced pressure. Compound 40B was isolated in the form of yellow oil, 2.1 g (96%).

Compound 40C: benzyl (S)-2-((4-((tert-butoxycarbonyl)(methyl)amino)butyl) (methyl)amino)-3-methylbutanoate

Compound 40C was synthesised in the same manner as for compound 14C from the amine 1ZC (2.45 g, 9.53 mmol, 0.80 equiv), the aldehyde 40B (2.4 g, 11.92 mmol, 1.00 equiv), NaBH(OAc)₃ (5.06 g, 23.87 mmol, 2.00 equiv) and DIEA (6.16 g, 47.66 mmol, 4.00 equiv) in THF (15 mL). The reaction mixture was neutralised with 100 mL of water and extracted twice with 100 mL of AcOEt. The organic phases were combined, dried over sodium sulfate, filtered and concentrated. The residue was purified on silica gel (EtOAc/PE (1:100-1:20)) to yield 1.2 g (25%) of compound 40C in the form of a yellow oil.

Compound 40D: (S)-2-((4-((tert-butoxycarbonyl)(methyl)amino)butyl) (methyl)amino)-3-methylbutanoic acid

Compound 40C (500 mg, 1.23 mmol, 1.00 equiv) was dissolved in 20 mL of EtOH in the presence of Pd/C (550 mg) and hydrogenated for 1 hour at ambient temperature and atmospheric pressure. The reaction medium was filtered and concentrated under reduced pressure to yield 350 mg (90%) of compound 40D in the form of a colourless oil.

Compound 40E: tert-butyl ((3R,4S,7S,10S)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2-oxa-5,8,11-triazapentadecan-15-yl)(methyl)carbamate

Compound 40E was synthesised in the same manner as for compound 3 from the amine 1Y (60 mg, 0.09 mmol, 1.00 equiv), the acid 40D (57.8 mg, 0.18 mmol, 2.00 equiv), DEPC (0.0278 mL) and DIEA (0.0452 mL) in DCM (3 mL). The crude product (100 mg) was subsequently used as such.

Compound 40: Compound 40 was synthesised in the same manner as for compound 2 from the intermediate 40E (100 mg, 0.10 mmol, 1.00 equiv). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×100 mm Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 95% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 40 was obtained with a yield of 24% (24.6 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₆H₇₇N7O₆S, exact mass 855.6) m/z: 856.6 (MH⁺) and 428.8 (M.2H⁺/2, 100%), 5.89 min (97.0%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.9-8.5 (0.7H, NHCO incomplete exchange), 7.8-7.7 (m, 1H), 7.55-4.45 (m, 1H), 7.35-7.1 (m, 5H), 5.5-5.75 (m, 1H), 4.9-4.6 (m, 2H), 4.2-0.8 (m, 64H).

Compound 41 methyl (S)-2-((2R,3R)-3-((S)-1-((8S,11S,14S,15R)-14-((S)-sec-butyl)-8,11-diisopropyl-15-methoxy-7,13-dimethyl-9,12-dioxo-2,7,10,13-tetraazaheptadecan-17-oyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, bis trifluoroacetic acid

Compound 41A: methyl (S)-2-((2R,3R)-3-((S)-1-((11S,14S,17S,18R)-17-((S)-sec-butyl)-11,14-diisopropyl-18-methoxy-2,2,5,10,16-pentamethyl-4,12,15-trioxo-3-oxa-5,10,13,16-tetraazaicosan-20-oyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate

Compound 41A was synthesised in the same manner as for compound 3 from the amine 3D (170 mg, 0.27 mmol, 1.00 equiv), the acid 40D (170 mg, 0.54 mmol, 2.09 equiv), DEPC (0.0819 mL) and DIEA (0.133 mL) in DCM (5 mL). The crude product (200 mg) was subsequently used as such.

Compound 41: Compound 41 was synthesised in the same manner as for compound 2 from the intermediate 41A (100 mg, 0.11 mmol, 1.00 equiv). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 95% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 41 was obtained with a yield of 25% (25 mg) in the form of a white solid.

LC/MS/UV (Agilent Zorbax SB-Aq column, 1.8 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 2% MeOH in water (0.05% TFA) for 1 minute then 2% to 95% MeOH in water in 13 minutes, then 95% MeOH in water for 2 minutes); ESI (C₄₅H₇₈N₆O₈, exact mass 830.6) m/z: 831.6 (MH⁺) and 416.4 (M.2H⁺/2, 100%), 11.58 min (97.2%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.55-8.15 (0.75H, NHCO incomplete exchange), 7.30-7.1 (m, 5H), 4.9-4.6 (m, 3H), 4.2-0.8 (m, 67H).

Compound 42 (S)-2-((2R,3R)-3-((S)-1-((8S,11S,14S,15R)-14-((S)-sec-butyl)-8,11-diisopropyl-15-methoxy-7,13-dimethyl-9,12-dioxo-2,7,10,13-tetraazaheptadecan-17-oyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, bis trifluoroacetic acid

Compound 42 was prepared in the same manner as for compound 4, from compound 41 (100 mg, 0.11 mmol, 1.00 equiv). The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, Atlantis Prep OBD T3 column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm), to yield 30.6 mg (31%) of compound 42 in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 0% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₄H₇₆N6O₈, exact mass 816.6) m/z: 817.6 (MH⁺) and 409.4 (M.2H⁺/2, 100%), 5.75 min (100%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.5-8.1 (0.3H, NHCO incomplete exchange), 7.30-7.1 (m, 5H), 4.9-4.6 (m, 3H), 4.2-0.8 (m, 64H).

Compound 43 (S)—N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethyl-2-((R)-3-methyl-2-(methyl(2-(2-(methylamino) ethoxy)ethyl)amino)butanamido)butanamide, bis trifluoroacetic acid

Compound 43A: tert-butyl (2-(2-((tertbutyldimethylsilyl)oxy)ethoxy)ethyl) carbamate

Compound 35A (tert-butyl ((2-(2-hydroxyethoxy)ethyl)carbamate) (8.21 g, 40.00 mmol, 1.00 equiv) and imidazole (6 g, 88.14 mmol, 2.20 equiv) were dissolved in an inert atmosphere in DCM (200 mL). Tertbutyldimethylsilane chloride (TBDMSCI, 6.62 g, 43.92 mmol, 1.10 equiv) was added drop-wise and the reaction medium was left under agitation overnight at ambient temperature. The reaction mixture was diluted with 100 mL of DCM then washed twice with 200 mL of 0.5 M HCl, twice with 200 mL of NaHCO₃ (sat.), then 300 mL of NaCl (sat.). The organic phase was dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified on silica gel (EtOAc/PE (1:3) to yield 10 g (78%) of compound 43A in the form of a white solid.

Compound 43B: tert-butyl (2-(2-((tert-butyldimethylsilyl)oxy)ethoxy) ethyl)(methyl)carbamate

Compound 43B was prepared in the same manner as for compound 11E, from compound 43A (10 g, 31.30 mmol, 1.00 equiv), NaH (60% in oil, 5 g, 208.33 mmol, 4.00 equiv) and iodomethane (22 g, 5.00 equiv) in DMF (200 mL). The reaction medium was neutralised with 200 mL of water and washed 3 times with 100 mL of AcOEt then 300 mL of NaCl (sat.). The organic phase was dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 10 g (96%) of compound 43B in the form of a white solid.

Compound 43C: tert-butyl (2-(2-hydroxyethoxy)ethyl)(methyl)carbamate

Compound 43B (10 g, 29.89 mmol, 1.00 equiv) and TBAF.3H₂O (20.8 g, 65.93 mmol, 2.20 equiv) were dissolved in THF (200 mL). The mixture was agitated at ambient temperature for 2 hours then extracted 3 times with 100 mL of AcOEt. The organic phases were recombined, washed twice with 300 mL of water, then twice with 300 mL of NaCl (sat.), dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified on silica gel (EtOAc/PE (1:3-1:1) to yield 6.6 g of compound 43C in the form of colourless oil.

Compound 43D: tert-butyl methyl(2-(2-oxoethoxy)ethyl)carbamate

Compound 43D was prepared in the same manner as for compound 35B, from compound 43C (2 g, 9.12 mmol, 1.00 equiv), oxalyl chloride (1.9 mL), TEA (11.3 mL) and DMSO (3.3 mL). Compound 43D (2 g) was isolated in the form of yellow oil.

Compound 43E: benzyl (S)-12-isopropyl-2,2,5,11-tetramethyl-4-oxo-3,8-dioxa-5,11-diazatridecan-13-oate

Compound 43E was synthesised in the same manner as for compound 14C from the amine 1ZC (2.4 g, 9.31 mmol, 1.00 equiv), the aldehyde 43D (2 g, 9.16 mmol, 1.00 equiv), NaBH(OAc)₃ (4 g, 18.87 mmol, 2.06 equiv) and DIEA (6 mL) in THF (100 mL). The reaction mixture was neutralised with 100 mL of water and extracted 3 times with 100 mL of AcOEt. The organic phases were combined, dried over sodium sulfate, filtered and concentrated. The residue was purified on silica gel (EtOAc/PE (4:1) to yield 1 g (37%) of compound 43E in the form of a white solid.

Compound 43F: (S)-12-isopropyl-2,2,5,11-tetramethyl-4-oxo-3,8-dioxa-5,11-diazatridecan-13-oic acid

Compound 43E (1 g, 2.37 mmol, 1.00 equiv) was dissolved in 40 mL of MeOH in the presence of Pd/C (1 g) and hydrogenated for 1 hour at ambient temperature and atmospheric pressure. The reaction medium was filtered and concentrated under reduced pressure to yield 600 mg (76%) of compound 43F in the form of a white solid.

Compound 43G: tert-butyl ((3R,4S,7S,10R)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2,14-dioxa-5,8,11-triazahexadecan-16-yl)(methyl)carbamate

Compound 43G was synthesised in the same manner as for compound 3 from the amine 1Y (50 mg, 0.08 mmol, 1.00 equiv), the acid 43F (50 mg, 0.08 mmol, 1.00 equiv), DEPC (24.79 mg, 0.15 mmol, 2.00 equiv) and DIEA (29.46 mg, 0.23 mmol, 3.00 equiv) in DCM (1 mL). The crude product (59 mg) was subsequently used as such.

Compound 43: Compound 43 was synthesised in the same manner as for compound 2 from the intermediate 43G (81 mg, 0.08 mmol, 1.00 equiv). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 95% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 43 was obtained with a yield of 64% (52.6 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% MeCN in water (0.05% TFA) for 8 minutes then 95% MeCN in water for 2 minutes); ESI (C₄₈H₇₇N₇O₇S, exact mass 871.6) m/z: 872.5 (MH⁺) and 436.9 (M.2H⁺/2, 100%), 3.90 min (100%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.8-7.7 (m, 1H), 7.55-4.45 (m, 1H), 7.35-7.1 (m, 5H), 5.5-5.75 (m, 1H), 4.9-4.6 (m, 2H), 4.2-0.8 (m, 64H).

Compound 44 methyl (S)-2-((2R,3R)-3-((S)-1-((9S,12S,15S,16R)-15-((S)-sec-butyl)-9,12-diisopropyl-16-methoxy-8,14-dimethyl-10,13-dioxo-5-oxa-2,8,11,14-tetraazaoctadecan-18-oyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, bis trifluoroacetic acid

Compound 44A: methyl (S)-2-((2R,3R)-3-((S)-1-((12S,15S,18S,19R)-18-((S)-sec-butyl)-12,15-diisopropyl-19-methoxy-2,2,5,11,17-pentamethyl-4,13,16-trioxo-3,8-dioxa-5,11,14,17-tetraazahenicosan-21-oyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate

Compound 44A was synthesised in the same manner as for compound 3 from the amine 3D (60 mg, 0.09 mmol, 1.00 equiv), the acid 43F (47 mg, 0.14 mmol, 1.50 equiv), DEPC (31 mg, 0.19 mmol, 2.00 equiv) and DIEA (37 mg, 0.28 mmol, 3.00 equiv) in DCM (1.5 mL). The crude product (58 mg) was subsequently used as such.

Compound 44: Compound 44 was synthesised in the same manner as for compound 2 from the intermediate 44A (58 mg, 0.06 mmol, 1.00 equiv). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 95% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 44 was obtained with a yield of 40% (23.7 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 mL/min, 10% to 95% MeCN in water (0.05% TFA) for 8 minutes then 95% MeCN in water for 2 minutes); ESI (C₄₅H₇₈N6O₉, exact mass 846.6) m/z: 847.6 (MH⁺) and 424.4 (M.2H⁺/2, 100%), 3.20 min (100%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.3-7.1 (m, 5H), 4.9-4.6 (m, 3H), 4.2-0.8 (m, 67H).

Compound 45 (S)—N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethyl-2-((S)-3-methyl-2-(methyl(2-(piperazin-1-yl)ethyl)amino)butanamido)butanamide, tris trifluoroacetic acid

Compound 45A: tert-butyl 4-(2-hydroxyethyl)piperazine-1-carboxylate

2-(piperazin-1-yl)ethan-1-ol (5 g, 38.41 mmol, 1.00 equiv) was dissolved in DCM (100 mL), and a solution of di-tert-butyl dicarbonate (8.38 g, 38.40 mmol, 1.00 equiv) in DCM (20 mL) was added drop-wise. The reaction was left under agitation overnight at ambient temperature. The reaction was evaporated to dryness and the residue dissolved in 200 mL of AcOEt, washed 5 times with NaCl (sat.), dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 8.5 g (96%) of compound 45A in the form of a white solid.

Compound 45B: tert-butyl 4-(2-oxoethyl)piperazine-1-carboxylate

Compound 45B was prepared in the same manner as for compound 35B, from compound 45A (1 g, 4.34 mmol, 1.00 equiv), oxalyl chloride (610 mg, 4.80 mmol, 1.12 equiv), TEA (2.13 g, 21.09 mmol, 4.90 equiv) and DMSO (0.82 g, 2.40 equiv). Compound 45B (0.8 g, 81%) was isolated in the form of a colourless oil.

Compound 45C: tert-butyl (S)-4-(2-((1-(benzyloxy)-3-methyl-1-oxobutan-2-yl)(methyl)amino)ethyl)piperazine-1-carboxylate

Compound 45C was synthesised in the same manner as for compound 14C from the amine 1ZC (720 mg, 2.79 mmol, 0.80 equiv), the aldehyde 45B (800 mg, 3.50 mmol, 1.00 equiv), NaBH(OAc)₃ (1.6 g, 7.55 mmol, 2.15 equiv) and DIEA (2.5 mL) in THF (50 mL). The reaction mixture was neutralised with 5 mL of water and extracted 3 times with 5 mL of AcOEt. The organic phases were combined, dried over sodium sulfate, filtered and concentrated. The residue was purified on silica gel (EtOAc/PE (3:1) to yield 400 mg (33%) of compound 45C in the form of a colourless oil.

Compound 45D: (S)-2-((2-(4-(tert-butoxycarbonyl)piperazin-1-yl)ethyl) (methyl)amino)-3-methylbutanoic acid

Compound 45C (400 mg, 0.92 mmol, 1.00 equiv) was dissolved in 30 mL of MeOH in the presence of Pd/C (400 mg) and hydrogenated for 1 hour at ambient temperature and atmospheric pressure. The reaction medium was filtered and concentrated under reduced pressure to yield 300 mg (95%) of compound 45D in the form of a white solid.

Compound 45E: tert-butyl 4-((3R,4S,7S,10S)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2-oxa-5,8,11-triazatridecan-13-yl)piperazine-1-carboxylate

Compound 45E was synthesised in the same manner as for compound 3 from the amine 1Y (60 mg, 0.09 mmol, 1.00 equiv), the acid 45D (62.7 mg, 0.18 mmol, 2.00 equiv), DEPC (0.0278 mL) and DIEA (0.0452 mL) in DCM (3 mL). The crude product (100 mg) was subsequently used as such.

Compound 45: Compound 45 was synthesised in the same manner as for compound 2 from the intermediate 45E (100 mg, 0.10 mmol, 1.00 equiv). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 95% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 45 was obtained with a yield of 19% (19.4 mg) in the form of a white solid.

LC/MS/UV (Agilent ZORBAX SB-Aq column, 1.8 μm, 4.6×100 mm; 40° C.; 1.0 mL/min, 2% MeOH in water (0.05% TFA) for 1 minute then 2% to 95% MeOH in water in 13 minutes then 95% MeOH in water for 2 minutes); ESI (C₄₇H₇₈N₈O₆S, exact mass 882.6) m/z: 883.5 (MH⁺) and 442.4 (M.2H⁺/2, 100%), 10.95 min (98.8%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers), 7.80-7.70 (m, 1H), 7.52-7.43 (m, 1H), 7.31-7.09 (m, 5H), 5.70-5.51 (m, 1H), 4.80-4.60 (m, 1H), 4.20-0.75 (m, 66H).

Compound 46 methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)—N,3-dimethyl-2-((S)-3-methyl-2-(methyl(2-(piperazin-1-yl)ethyl)amino)butanamido)butanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, tris trifluoroacetic acid

Compound 46A: tert-butyl 4-((3R,4S,7S,10S)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-3-(((S)-1-methoxy-1-oxo-3-phenylpropan-2-yl)amino)-2-methyl-3-oxopropyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2-oxa-5,8,11-triazatridecan-13-yl)piperazine-1-carboxylate

Compound 46A was synthesised in the same manner as for compound 3 from the amine 3D (170 mg, 0.27 mmol, 1.00 equiv) the acid 45D (184.6 mg, 0.54 mmol, 2.00 equiv), DEPC (0.0819 mL) and DIEA (0.133 mL) in DCM (5 mL). The crude product (200 mg) was subsequently used as such.

Compound 46: Compound 46 was synthesised in the same manner as for compound 2 from the intermediate 46A (100 mg, 0.10 mmol, 1.00 equiv). The crude product was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 95% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm). Compound 46 was obtained with a yield of 19% (19.1 mg) in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 m/min, 10% to 95% MeCN in water (0.05% TFA) for 8 minutes then 95% MeCN in water for 2 minutes); ESI (C₄₆H₇₉N₇O₈, exact mass 857.6) m/z: 858.6 (MH⁺) an 429.9 (M.2H⁺/2, 100%), 5.93 min (100%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.58-8.50 (m, 0.5 H, NHCO, incomplete exchange), 8.29-8.22 (m, 0.4 H, NHCO, incomplete exchange), 7.35-7.15 (m, 5H), 4.87-4.69 (m, 3H), 4.22-0.82 (m, 68H).

Compound 47 (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)—N,3-dimethyl-2-((S)-3-methyl-2-(methyl(2-(piperazin-1-yl)ethyl)amino)butanamido)butanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, tris trifluoroacetic acid

Compound 47 was prepared in the same manner as for compound 4, from compound 46 (100 mg, 0.10 mmol, 1.00 equiv). The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, Atlantis Prep OBD T3 column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm), to yield 32.6 mg (33%) of compound 47 in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 m/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₆H₇₇N₇O₈, exact mass 843.6) m/z: 844.6 (MH⁺) and 422.9 (M.2H⁺/2, 100%), 5.73 min (100%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.66-8.57 (m, 0.3 H, NHCO, incomplete exchange), 8.41-8.32 (m, 0.3 H, NHCO, incomplete exchange), 8.13-8.06 (m, 0.2 H, NHCO, incomplete exchange), 7.30-7.10 (m, 5H), 4.80-4.61 (m, 3H), 4.19-0.78 (m, 65H).

Compound 48 (S)-2-((S)-2-(((1H-imidazol-2-yl)methyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide, trifluoroacetic acid

Compound 48 was prepared in the same manner as for compound 1, from the amines 1Y and 1ZC and 1H-imidazole-2-carbaldehyde. The end product was purified by preparative HPLC under the following conditions: SunFire Prep C18 OBD column, 5 μm, 19x150 mm, mobile phases buffered with 0.05% TFA, gradient of 15.0 to 30% ACN in water in 10 minutes then up to 95.0% ACN in 2 minutes, UV Detection UV 220 nm.

LC/MS/UV (Zorbax Eclipse Plus C8, 1.8 μm, 4.6×100 mm; 1 m/min, 40° C., 2% methanol in water (eluting phases buffered with 0.05% TFA) for 1 minute, then 2% to 95% methanol for 12 minutes; ESI (C₄₅H₇₀N₈O₆S, exact mass 850.51) m/z: 851.2 (MH⁺), 873.5 (MNa⁺), 426.3 (M.2H⁺/2); 12.75 min (90.5%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.83-7.81 (m, 1H), 7.80-7.53 (m, 3H), 7.53-7.22 (m, 5H), 5.6-5.8 (m, 1H), 5.0-4.6 (m, 2H); 4.6-0.85 (m, 55H).

Compound 49 (S)-2-((S)-2-((4-hydroxyphenethyl)(mthyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-3-mthoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide, trifluoroacetic acid

Compound 49A: 2-(4-hydroxyphenyl)acetaldehyde

4-(2-hydroxyethyl)phenol (4 g, 28.95 mmol, 1.00 quiv) was dissolved in DMSO (32 mL) and TEA (8.8 mL, 2.20 equiv) was then added dropwise. A solution of SO₃.Py (10 g, 2.20 equiv) in DMSO (36 mL) was added and the mixture was left under agitation overnight at ambient temperature. The reaction mixture was neutralised with 250 mL of water and extracted 3 times with 100 mL of AcOEt. The organic phases were combined, washed 5 times with water (100 mL) then twice with 150 mL of NaCl (sat.), dried over sodium sulfate, filtered and concentrated. The residue was purified on silica gel (EtOAc/PE (1:10) to yield 1 g (25%) of compound 49A in the form of a colourless oil.

Compound 49B: benzyl (S)-2-((4-hydroxyphenethyl)(methyl)amino)-3-methylbutanoate

Compound 49B was synthesised in the same manner as for compound 14C from the amine 1ZC (1.5 g, 5.82 mmol, 0.99 equiv), the aldehyde 49A (800 mg, 5.88 mmol, 1.00 equiv), NaBH(OAc)₃ (2.7 g, 12.74 mmol, 2.17 equiv) and DIEA (4.23 mL) in THF (25 mL). The reaction mixture was neutralised with 50 mL of water and extracted 3 times with 50 mL of AcOEt. The organic phases were combined, dried over sodium sulfate, filtered and concentrated. The residue was purified on silica gel (EtOAc/PE (1:10) to yield 600 mg (37%) of compound 49B in the form of a white solid.

Compound 49C: (S)-2-((4-hydroxyphenethyl)(methyl)amino)-3-methylbutanoic acid

Compound 49B (0.5 g, 1.46 mmol, 1.00 equiv) was dissolved in 40 mL of MeOH in the presence of Pd/C (250 mg) and hydrogenated for 3 hours at ambient temperature and atmospheric pressure. The reaction medium was filtered and concentrated under reduced pressure to yield 0.4 g of compound 49C in the form of a white solid.

Compound 49: Compound 49 was synthesised in the same manner as for compound 3 from the amine 1Y (53.4 mg, 0.08 mmol, 2.00 equiv), the acid 49C (70 mg, 0.28 mmol, 1.00 equiv), DEPC (0.032 mL, 2.00 equiv) and DIEA (0.053 mL, 3.00 equiv) in DCM (3 mL). The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, Atlantis Prep OBD T3 column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 45% ACN in 10 minutes then 45% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm), to yield 3 mg (1%) of compound 49 in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 m/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₉H₇₄N₆O₇S, exact mass 890.5) m/z: 891.5 (MH⁺) and 446.4 (M.2H⁺/2, 100%), 6.69 min (100%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.92-8.87 (m, 0.5 H, NHCO, incomplete exchange), 8.70-8.63 (m, 0.4 H, NHCO, incomplete exchange), 8.85-8.77 (m, 1H), 7.59-7.51 (m, 1H), 7.35-7.03 (m, 7H), 6.82-6.71 (m, 2H), 5.77-5.58 (m, 11H), 5,81-5.70 (m, 11H), 4.21-0.80 (m, 58H).

Compound 50 (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-hydroxyphenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoic acid, trifluoroacetic acid

Compound 50 was prepared in the same manner as for compound 4, from compound 27 (100 mg, 0.10 mmol, 1.00 equiv). The residue was purified by preparative HPLC (Pre-HPLC-001 SHIMADZU, Atlantis Prep OBD T3 column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 20% to 40% ACN in 10 minutes then 40% to 100% ACN in 2 minutes; Waters 2545 UV Detector at 254 nm and 220 nm), to yield 10.7 mg (11%) of compound 50 in the form of a white solid.

LC/MS/UV (Ascentis Express C18 column, 2.7 μm, 4.6×100 mm; 40° C.; 1.5 m/min, 10% to 95% MeOH in water (0.05% TFA) in 8 minutes); ESI (C₄₇H₇₃N₅O₉, exact mass 851.5) m/z: 852.5 (MH⁺) and 426.8 (M.2H⁺/2, 100%), 6.46 min (91.7%, 210 nm).

¹H NMR: (400 MHz, CD₃OD, ppm): δ (Presence of rotamers) 7.34-7.15 (m, 5H); 7.15-7.04 (se, 2H), 6.82-6.83 (m, 2H), 4.83-4.70 (m, 1H), 4.21-4.00 (m, 1H), 3.90-3.80 (m, 1H), 3.74-3.62 (m, 1H), 3.57-2.86 (m, 20H), 2.56-0.80 (m, 36H).

Compound 51 methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-hydroxybenzyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate, trifluoroacetic acid

Compound 51A: tert-butyl (4-formylphenyl)carbonate

4-hydroxybenzaldehyde (3.0 g, 24 mmol) was dissolved in 30 mL of DCM in the presence of 4-DMAP (300 mg, 2.46 mmol, 0.1 equiv.) and di-tert-butyl dicarbonate (5.35 g, 24 mmol, 1.0 equiv.) and agitated 1 hour at ambient temperature. The solution was then diluted with 200 mL of water and extracted 3 times with 100 mL of DCM. The organic phases were combined, dried over sodium sulfate, filtered and concentrated under reduced pressure to yield 5 g (92%) of compound 51A in the form of a white solid.

Compound 51B: benzyl (S)-2-((4-((tert-butoxycarbonyl)oxy)benzyl)(methyl)amino)-3-methylbutanoate

Compound 51A (220 mg, 0.99 mmol) was dissolved in 5 mL of THF in the presence of compound 1ZC (255 mg, 0.99 mmol, 1.0 equiv.), NaBH(OAc)₃ (420 mg, 2 mmol, 2.0 equiv.) and DIEA (654 μl) and agitated overnight at ambient temperature. The solution was then diluted with 100 mL of water and extracted 3 times with 50 mL of EtOAc. The organic phases were combined, dried over sodium sulfate, filtered and concentrated under reduced pressure. The residue was purified on a silica column with a mixture of EtOAc and PE (1:100) to yield 200 mg (47%) of compound 51B in the form of a white solid.

Compound 51C: (S)-2-((4-((tert-butoxycarbonyl)oxy)benzyl)(methyl)amino)-3-methyl butanoic acid

Compound 51C was prepared by hydrogenation of compound 51B (200 mg), following the protocol used for the preparation of compound 3F.

Compound 51D: methyl (S)-2-((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((tert-butoxycarbonyl)oxy)benzyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanamido)-3-phenylpropanoate

Compound 51D was prepared by coupling compound 51C with amine 3D, following the protocol used for the preparation of compound 3 to obtain the desired product in the form of yellow oil with a yield of 60%.

Compound 51: Compound 51D (80 mg, 0.08 mmol) was dissolved in 1 mL of DCM in the presence of 0.5 mL TFA, agitated 2 hours at ambient temperature and then concentrated under reduced pressure. The residue was purified by preparative HPLC (Pre-HPLC-010, SunFire Prep C18 OBD column, 5 μm, 19×150 mm; Eluting phase: water/ACN buffered with 0.05% TFA; Gradient of 23% to 40% ACN in 10 minutes then 40% to 95% ACN in 2 minutes; Waters 2489 UV Detector at 254 nm and 220 nm). Compound 51 was obtained with a yield of 24% (20 mg) in the form of a white solid.

LC/MS/UV (Zorbax SB-Aq, 1.8 μm, 4.6×100 mm; 2% MeOH in water (0.05% TFA) for 1 minute then 2% to 95% MeOH in 13 minutes); ESI (C₄₇H₇₃N₅O₉, exact mass 851.54) m/z: 874.5 (MNa⁺), 426.9 (M.2H⁺/2); 12.48 min (96%, 210 nm).

¹H NMR: (300 MHz, CD₃OD, ppm): δ (Presence of rotamers) 8.1-8.6 (m, 0.9H, NHCO incomplete exchange); 7.29-7.27 (m, 2H), 7.25-6.86 (m, 5H), 6.84-6.83 (m, 2H), 4.83-4.72 (m, 3H), 4.26-0.82 (m, 58H).

Compound 61 (S)-2-((S)-2-((4-aminophenethyl)(methyl)amino)-3-methylbutanamido)-N-((3R,4S,5S)-3-methoxy-1-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-5-methyl-1-oxoheptan-4-yl)-N,3-dimethylbutanamide

Compound 61A: N-(4-aminophenethyl)-N-methyl-L-valine dihydrochloride

Compound 11D (962 mg, 2.75 mmol) was dissolved in 10 ml of a commercially available solution of HCl in propan-2-ol (5-6 M), and stirred at room temperature for 2 hours. TLC analysis indicated complete consumption of starting material. The solvent was evaporated under reduced pressure, and the resulting yellow solid triturated with Et₂O (2×10 ml). The product was dried under vacuum to furnish compound 61A as a yellow solid (322 mg, 47%).

Compound 61: Carboxylic acid 61A (73 mg, 0.23 mmol, 1 eq.) and amine 1Y (150 mg, 0.23 mmol, 1 eq.) were dissolved in dry DMF (2 ml). DIEA (158 μl, 0.90 mmol, 4 eq.) and DECP (51 μl, 0.34 mmol, 1.5 eq.) were added and the reaction stirred for 4 hours at room temperature. Analysis by LC-MS showed complete consumption of the starting material. The solvent was evaporated under reduced pressure, and the residue purified by flash chromatography on silica gel (DCM/MeOH) to furnish compound 61 as a light yellow solid (83 mg, 40%).

¹H NMR: (500 MHz, DMSO-d₆, ppm): δ (Presence of rotamers), 8.86 (d, 0.5H, NHCO); 8.65 (d, 0.5H, NHCO), 8.11-8.05 (m, 1H, NHCO), 7.80 (d, 0.5H, thiazole), 7.78 (d, 0.5H, thiazole), 7.65 (d, 0.5H, thiazole), 7.63 (d, 0.5H, thiazole), 7.32-7.12 (m, 5H), 6.83 (d, J=8.3 Hz, 2H), 6.45 (d, J=8.3 Hz, 2H), 5.56-5.49 (m, 0.5 H), 5.42-5.35 (m, 0.5H), 4.78 (s, 2H, NH₂), 4.74-4.46 (m, 2H), 4.01-0.66 (m, 57H).

HPLC (Xbridge Shield C18, 3.5 μm, 4.6×50 mm; 3.5 ml/min, 40° C., 0 to 95% MeCN in water (0.1% TFA) in 2.25 minutes then 95% MeCN for 0.5 minutes, Tr=1.31 min (96.5%, 220 nm).

m/z (Q-TOF ESI⁺) 890.5558 (2%, MH⁺, C₄₉H₇₆N₇O₆S requires 890.5572), 445.7834 (100%, (MH₂)²⁺, C₄₉H₇₇N₇O₆S requires 445.7823).

Compound 62 Methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-aminophenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate

Compound 62 was prepared in the same manner as for compound 61, using carboxylic acid 61A (69 mg, 0.21 mmol, 1 eq.), amine 3D (135 mg, 0.21 mmol, 1 eq.), DIEA (75 μl, 0.43 mmol, 2 eq.) and DECP (49 μl, 0.32 mmol, 1.5 eq.). The crude product was purified by flash chromatography on silica gel (DCM/MeOH) to furnish compound 62 as a yellowish solid (82 mg, 45%).

¹H NMR: (500 MHz, DMSO-d₆, ppm): δ (Presence of rotamers), 8.50 (d, J=8.3, 0.5H, NHCO); 8.27 (d, J=8.0, 0.5H, NHCO), 8.15-8.04 (m, 1H, NHCO), 7.27-7.13 (m, 5H), 6.86-6.79 (m, 2H), 6.48-6.42 (m, 2H), 4.78 (s, 2H, NH₂), 4.74-4.44 (m, 3H), 4.01-3.72 (m, 1.5H), 3.66 (s, 1.5H, CO₂Me), 3.63 (s, 1.5H, CO₂Me), 3.57-0.65 (m, 55.5H).

HPLC (Xbridge Shield C18, 3.5 μm, 4.6×50 mm; 3.5 ml/min, 40° C., 0 to 95% MeCN in water (0.1% TFA) in 2.25 minutes then 95% MeCN for 0.5 minutes, Tr=1.29 min (95.3%, 220 nm).

m/z (Q-TOF ESI⁺) 865.5800 (2%, MH⁺, C₄₈H₇₇N₆O₈ requires 865.5797), 433.2937 (100%, (MH₂)²⁺, C₄₈H₇₈N₆O₈ requires 433.2935).

Compound 63 ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-aminophenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalanine 2,2,2-trifluoroacetate

Compound 62 (23 mg, 0.03 mmol) was dissolved in a mixture of water (1 ml) and acetonitrile (1 ml). Piperidine (0.75 ml) was added and the mixture stirred at room temperature for 5 hours. TLC analysis indicated complete consumption of the starting material. The solvent was evaporated under reduced pressure, and the residue purified by preparative HPLC (SunFire Prep column C18 OBD, 5 μm, 19×150 mm; Mobile phase: water/MeCN buffered with 0.1% TFA; Gradient of 20% to 40% MeCN in 10 minutes, then from 40% to 100% MeCN in 2 minutes; Detector UV Waters 2545 at 254 nm et 220 nm). Compound 63 was obtained as a white solid (14 mg, 66%).

¹H NMR: (500 MHz, DMSO-d₆, ppm): δ (Presence of rotamers), 12.7 (s(br), 1H, CO₂H), 9.58 (m(br), 1H); 9.04-8.89 (m, 1H), 8.41 (d, 0.6H, NHCO), 8.15 (d, 0.4H, NHCO), 7.27-7.13 (m, 5H), 7.13-6.99 (m(br), 2H), 6.90-6.64 (s(br), 2H), 4.77-3.40 (m, 10H), 3.34-2.75 (m, 20H), 2.34-1.94 (m, 4H), 1.90-0.7 (m, 25H).

HPLC (Xbridge Shield C18, 3.5 μm, 4.6×50 mm; 3.5 ml/min, 40° C., 0 to 95% MeCN in water (0.1% TFA) in 2.25 minutes then 95% MeCN for 0.5 minutes, Tr=1.24 min (100%, 220 nm).

m/z (Q-TOF ESI⁺) 851.5641 (6%, MH⁺, C₄₇H₇₅N6O₈ requires 851.5641), 426.2854 (100%, (MH₂)²⁺, C₄₇H₇₆N₆O₈ requires 426.2857).

Example 20: Antiproliferative activity of the Drugs

Method:

Cell culture. A549 (Non Small Cell Lung Cancer-ATCC CCL-185) and MDA-MB-231 (breast adenocarcinoma-ATCC HTB-26) cells were cultured in Minimum Essential Medium Eagle (MEM) with 5% fetal calf serum (FCS) and Dulbecco's modified Eagle Medium (DMEM) with 10% FCS respectively. MCF7 (breast ductal carcinoma-ATCC HTB-22) and SN-12C (kidney carcinoma-ATCC) cells were maintained in RPMI1640 medium (without phenol red for MCF7 cells) containing 10% FCS. All the media were supplemented with fungizone (1.25 μg/mL) and penicillin-streptomycin (100U/100 μg/mL). Cells were cultured under standard conditions in an incubator at 37° C., 5% CO₂ and 95% atmospheric humidity.

Antiproliferative activity on 4 tumor cell lines. Selected drugs were investigated for their antiproliferative activity using an ATPlite proliferation assay (Perkin Elmer, Villebon sur Yvette, France) on a comprehensive panel of 4 cell lines. Cells were seeded in 96 well plates (10³ cells/well for A549, 2.10³ for MCF7, MDA-MB-231 and SN12C) at day 0 at a concentration to ensure cells remained in logarithmic cell growth phase throughout the 72 h drug treatment period. After a 24 h incubation period, all the cells were treated with serial dilutions of the tested compounds (11 μL of a 10X solution in 1% DMSO-6 wells/condition). To avoid adherence of the compounds onto the tips, tips were changed between two consecutive dilutions. Cells were then placed in 37° C., 5% CO₂ incubator. On day 4, cell viability was evaluated by dosing the ATP released by viable cells. The number of viable cells was analyzed in comparison with the number of solvent treated cells. The EC₅₀ values were determined with curve fitting analysis (non linear regression model with a sigmoidal dose response, variable hill slope coefficient), performed with the algorithm provided by the GraphPad Software (GraphPad Software Inc., CA, USA).

Results:

Various Drugs:

Various drugs were tested to determine their antiproliferative activity on the MDA-MB-231 cell line following the above-described method. The measured activities gave values of EC₅₀<0.1 μM.

The few following examples chosen from among the above exemplified drugs illustrate their fully remarkable antiproliferative properties:

Example 12: EC₅₀=5.80x10⁻¹⁰ M; Example 13: EC₅₀=7.95×10⁻⁸ M; Example 15: EC₅₀=1.70×10⁻¹⁰ M; Example 27: EC₅₀=1.20x10⁻¹⁰ M

Various Cell Lines:

Compound 15 was tested on different cell lines (A549, MDA-MB-231, MCF-7, SN12C) following the above-described method. The measured activities gave values of EC₅₀<0.1 μM on all the tested cell lines.

EC₅₀ (M) A549 MDA-MB-231 MCF-7 SN12C Compound 15 1.45 × 10⁻¹⁰ 1.70 × 10⁻¹⁰ 7.15 × 10⁻¹⁰ 2.18 × 10⁻¹⁰

Comparative Examples

The substitution on the phenyl ring (amino/hydroxyl v. carboxyl) was studied in the comparative examples below showing the improved antiproliferative activity of the drugs according to the invention comprising an amino or hydroxyl substituent.

EC₅₀ (M) MDA- N^(o) Structure A549 MB-231 12

1.48 × 10⁻¹⁰ 5.80 × 10⁻¹⁰ 15

1.45 × 10⁻¹⁰ 1.70 × 10⁻¹⁰ 27

8.60 × 10⁻¹¹ 1.20 × 10⁻¹⁰ Com- parative example

3.76 × 10⁻⁹  2.29 × 10⁻⁹  13

2.71 × 10⁻⁸  7.95 × 10⁻⁸  Com- parative example

4.03 × 10⁻⁷  9.75 × 10⁻⁷ 

Example 21: Synthesis of the Drug-Linker moiety Compound E-11 4-((S)-2-((S)-2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamido)-3-methylbutanamido)-5-ureidopentanamido)benzyl (4-((3R,4S,7S,10S)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2-oxa-5,8,11-triazatridecan-13-yl)phenyl)(methyl)carbamate 2,2,2-trifluoroacetate

Compound E-11-1: methyl (S)-2-amino-5-ureidopentanoate hydrochloride

Acetyl chloride (10 mL) was added dropwise to MeOH (120 mL) at 0° C. with stirring. After 20 minutes, L-Citrulline (10 g, 57 mmol, 1.00 eq.) was added and the mixture heated at reflux overnight. The solvent was evaporated under reduced pressure to yield 15 g (116%) of compound E-11-1 as a white solid. The product was used in the next step without further drying.

Compound E-11-2: methyl (S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-5-ureidopentanoate

Compound E-11-1 (13 g, 57.6 mmol, 1.1 eq.) was dissolved in DMF (140 mL) at 0° C. under an inert atmosphere. DIEA (30 mL, 173 mmol, 3.0 eq.), hydroxybenzotriazole (HOBt-10.59 g, 69.1 mmol, 1.2 eq.) and Boc-L-valine hydroxysuccinimide ester (Boc-Val-OSu-18.1 g, 57.6 mmol, 1.0 eq.) were added. The reaction mixture was agitated overnight at ambient temperature, then the solvent was evaporated under reduced pressure. The residue was dissolved in water (100 mL) and extracted twice with DCM (150 mL). The organic phases were combined, dried over Na₂SO₄ and concentrated under reduced pressure. The residue was purified on silica gel (DCM/MeOH) to yield 18.8 g (84%) of compound E-11-2 as a white solid.

Compound E-11-3: (S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methyl butanamido)-5-ureidopentanoic acid

Compound E-11-2 (18.8 g, 48.4 mmol, 1 eq.) was dissolved in MeOH (200 mL) at 0° C. A solution of NaOH 1M (72 mL, 72 mmol, 1.5 eq.) was added and the mixture stirred for 2 hours at room temperature. The MeOH was removed under reduced pressure and the remaining aqueous solution acidified with HCl 1M. The aqueous phase was evaporated to dryness and the residue purified on silica gel (DCM/MeOH) to yield 18 g (99%) of compound E-11-3 as a white solid.

Compound E-11-4: tert-butyl ((S)-1-(((S)-1-((4-(hydroxymethyl)phenyl) amino)-1-oxo-5-ureidopentan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)carbamate

Compound E-11-3 (5 g, 13.4 mmol, 1 eq.) was dissolved in a mixture of dry DCM (65 ml) and dry MeOH (35 ml). (4-aminophenyl)methanol (1.81 g, 14.7 mmol, 1.1 eq.) and N-Ethoxycarbonyl-2-ethoxy-1,2-dihydroquinoline (EEDQ-6.60 g, 26.7 mmol, 2 eq.) were added and the mixture stirred in the dark overnight. The solvents were evaporated under reduced pressure, and the residue purified on silica gel (DCM/MeOH) to yield 5.2 g (73%) of compound E-11-4 as an off-white solid.

Compound E-11-5: tert-butyl ((S)-3-methyl-1-(((S)-1-((4-((((4-nitrophenoxy)carbonyl)oxy)methyl)phenyl)amino)-1-oxo-5-ureidopentan-2-yl)amino)-1-oxobutan-2-yl)carbamate

Compound E-11-4 (1.1 g, 2.29 mmol, 1 eq.) was dissolved in dry DMF (5 ml) at ambient temperature under an inert atmosphere. Bis(4-nitrophenyl) carbonate (1.40 g, 4.59 mmol, 2 eq.) was added, followed by DIEA (600 μl, 3.44 mmol, 1.5 eq.), and the resulting yellow solution stirred overnight. The DMF was evaporated under reduced pressure, and the residue purified on silica gel (DCM/MeOH) to yield 1.27 g (84%) of compound E-11-5 as an off-white solid.

Compound E-11-6: 4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-5-ureidopentanamido)benzyl (4-((3R,4S,7S,10S)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2-oxa-5,8,11-triazatridecan-13-yl)phenyl)(methyl)carbamate 2,2,2-trifluoroacetate

Carbonate E-11-5 (114 mg, 0.177 mmol, 1.2 eq.) and aniline 11F (150 mg, 0.147 mmol, 1 eq.) were dissolved in dry DMF (4 mL). HOBt (38 mg, 0.295 mmol, 2 eq.) and DIEA (54 μL, 0.295 mmol, 2 eq.) were added and the mixture stirred for the weekend at room temperature. The DMF was evaporated under reduced pressure and the residue purified by flash chromatography on silica, eluting with DCM. The product was repurified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound E-11-6 as a white solid (89 mg, 39%).

Compound E-11

Compound E-11-6 (21 mg, 0.014 mmol, 1.0 eq.) was dissolved in DCM (0.25 mL) and TFA (40 μL) was added. The solution was stirred for 2 hours at room temperature, after which, LC-MS analysis indicated complete consumption of starting material. The mixture was briefly cooled (bath of liquid nitrogen) whilst simultaneously adding DMF (0.5 mL) then DIEA (100 μL) in order to neutralise the TFA. The cooling bath was then removed and 2,5-dioxopyrrolidin-1-yl 6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoate (4 mg, 0.012 mmol, 1 eq.) was added. The mixture was stirred at room temperature for 48 hours and the product purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound E-11 as a white solid (11 mg, 54%).

m/z (Q-TOF MS ESI+) 1524.8282 (2%, MNa⁺, C79H₁₁₅N₁₃NaO14S requires 1524.8299), 751.9283 (100%, (MH₂)²⁺, C₇₉H₁₁₇N₁₃O₁₄S requires 751.9276).

Compound E-12 methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((((4-((S)-2-((S)-2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamido)-3-methylbutanamido)-5-ureidopentanamido)benzyl)oxy)carbonyl)(methyl)amino)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate 2,2,2-trifluoroacetate

Compound E-12-1: tert-butyl ((S)-3-methyl-1-oxo-1-(((S)-1-oxo-1-((4-((((perfluorophenoxy)carbonyl)oxy)methyl)phenyl)amino)-5-ureidopentan-2-yl)amino)butan-2-yl)carbamate

Compound E-11-4 (670 mg, 1.26 mmol, 1 eq.) was dissolved in dry DMF (6 ml) at 0° C. under an inert atmosphere. Bis(perfluorophenyl) carbonate (991 mg, 2.51 mmol, 2 eq.) was added, followed by DIEA (329 μl, 1.89 mmol, 1.5 eq.), and the resulting colourless solution stirred for 30 minutes at room temperature. The DMF was evaporated under reduced pressure, and the residue purified on silica gel (DCM/MeOH) to yield 836 mg (96%) of compound E-12-1 as an off-white solid.

Compound E-12-2: methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((((4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-5-ureidopentanamido)benzyl)oxy)carbonyl)(methyl)amino)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate 2,2,2-trifluoroacetate

Aniline 12 (165 mg, 0.189 mmol, 1.0 eq.) was dissolved in DMF (5 mL) at 0° C. under an inert atmosphere. Carbonate E-12-1 (194 mg, 0.282 mmol, 1.5 eq.), HOBt (51 mg, 0.375 mmol, 2 eq.) and DIEA (66 μL, 0.375 mmol, 2 eq.) were added and the mixture stirred at room temperature for 8 hours. The solvent was evaporated under reduced pressure and the residue purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound E12-7 as a white solid (247 mg, 77%).

Compound E-12-3: methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((((4-((S)-2-((S)-2-amino-3-methylbutanamido)-5-ureidopentanamido)benzyl)oxy) carbonyl)(methyl)amino)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate bis(2,2,2-trifluoroacetate)

Compound E-12-2 (5.6 mg, 4.04 μmol, 1.0 eq.) was dissolved TFA (100 μL). After 5 minutes, 2 ml of water was added and the mixture lyophilised overnight to yield compound E-12-3 as an off-white solid (5.6 mg. 98%).

Compound E-12

Compound E-12-3 (5.6 mg, 4 μmol, 1.0 eq.) was dissolved in acetonitrile (0.5 mL), and DIEA (5 μL, 7 eq.) was added, followed by 2,5-dioxopyrrolidin-1-yl 6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoate (2.5 mg, 8 μmol, 2 eq.). The mixture was stirred for 6 hours at room temperature. After controlling the reaction by LC-MS, 200 μL of water was added, and the resulting solution purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound E-12 as a white solid (4.6 mg, 70%).

m/z (Q-TOF MS ESI+) 739.4389 (100%, (MH₂)²⁺, C₇₈H₁₁₈N₁₂O₁₆ requires 739.4389).

Compound E-13 ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((((4-((S)-2-((S)-2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamido)-3-methylbutanamido)-5-ureidopentanamido)benzyl)oxy)carbonyl)(methyl)amino)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalanine 2,2,2-trifluoroacetate

Compound E-13-1: ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((((4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-5-ureidopentanamido)benzyl)oxy)carbonyl)(methyl)amino)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalanine

Compound E-12-2 (185 mg, 0.123 mmol, 1.0 eq.) was dissolved in a mixture of water (5 mL) and acetonitrile (5 mL) at room temperature. Piperidine (3.67 mL, 300 eq.) was added and the mixture stirred for 6 hours at room temperature. The solvents were evaporated to dryness under reduced pressure, and the residue triturated with Et₂O (60 mL). The solid was rinsed with twice Et₂O (20 ml) and dried under vacuum to yield compound E-13-1 as an off-white solid (175 mg, 95%).

Compound E-13-2: ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((((4-((S)-2-((S)-2-amino-3-methylbutanamido)-5-ureidopentanamido)benzyl)oxy)carbonyl)(methyl)amino)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalanine bis (2,2,2-trifluoroacetate)

Compound E-13-1 (175 mg, 0.128 mmol, 1.0 eq.) was dissolved TFA (200 μL). After 5 minutes, water (1 mL) and acetonitrile (1 mL) were added and the solution lyophilised overnight to yield compound E-13-2 as an off-white solid (180 mg, 87%).

Compound E-13: ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((((4-((S)-2-((S)-2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamido)-3-methylbutanamido)-5-ureidopentanamido)benzyl)oxy)carbonyl)(methyl)amino)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl) pyrrolidin-2-yl-3-methoxy-2-methylpropanoyl-L-nhenvlalanine, 2,2,2-trifluoroacetate

Compound E-13-2 (80 mg, 0.058 mmol, 1.0 eq.) was dissolved in a mixture of acetonitrile (1.5 mL) and DMF (0.4 mL). DIEA (50 μL, 0.289 mmol, 5 eq.) was added, followed by 2,5-dioxopyrrolidin-1-yl 6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoate (36 mg, 0.116 mmol, 2 eq.). The mixture was stirred for 3 hours at room temperature. After controlling the reaction by LC-MS, the solvent was evaporated under reduced pressure and the residue purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound E-13 as a white solid (32 mg, 35%).

m/z (Q-TOF MS ESI−) 1461.8336 (100%, (M-H)⁻, C₇₇H₁₁₃N₁₂O₁₆ requires 1461.8403). m/z (Q-TOF MS ESI+) 1463.8565 (2%, MH⁺, C₇₇H₁₁₅N₁₂O₁₆ requires 1463.8549), 732.4317 (100%, (MH₂)²⁺, C₇₇H₁₁₆N₁₂O₁₆ requires 732.4311).

Compound E-15 methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((3-((((4-((S)-2-((S)-2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamido)-3-methylbutanamido)-5-ureidopentanamido)benzyl)oxy)carbonyl)amino)benzyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate 2,2,2-trifluoroacetate

Compound E-15-1: methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((3-((((4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-5-ureidopentanamido)benzyl)oxy)carbonyl)amino)benzyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate 2,2,2-trifluoroacetate

Compound E-15-1 was prepared according to the same method as for compound E-11-6, using carbonate E-11-5 (28 mg, 0.044 mmol, 1 eq.), aniline 15 (42 mg, 0.044 mmol, 1 eq.), HOBt (3 mg, 0.022 mmol, 0.5 eq.), and DIEA (15 μL, 0.087 mmol, 2 eq.) in DMF (2 mL). Compound E-15-1 was isolated as a white solid (8.2 mg, 13%).

Compound E-15-2: methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((3-((((4-((S)-2-((S)-2-amino-3-methylbutanamido)-5-ureidopentanamido)benzyl)oxy) carbonyl)amino)benzyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate bis(2,2,2-trifluoroacetate)

Compound E-15-1 (8.2 mg, 5.58 μmol, 1.0 eq.) was dissolved in TFA (200 μL). After 5 minutes, water (1 mL) was added and the solution lyophilised overnight to yield compound E-15-8 as a white solid (7.6 mg, 99%).

Compound E-15

Compound E-15 was prepared according to the same method as for compound E-12, using amine E-15-2 (7.6 mg, 5.55 μmol, 1 eq.), 2,5-dioxopyrrolidin-1-yl 6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoate (2 mg, 6.65 μmol, 1.2 eq.) and DIEA (5 μL, 0.028 mmol, 5 eq.) in acetonitrile (0.5 mL). Compound E-15 was isolated as a white solid (4.2 mg, 48%).

m/z (Q-TOF MS ESI+) 1471.8169 (2%, MNa⁺, C₇₆H₁₁₂N₁₂NaO₁₆ requires 1471.8211), 725.4223 (100%, (MH₂)²⁺, C₇₆H₁₁₄N₁₂O₁₆ requires 725.4232), 483.9482 (10%, (MH₃)³⁺, C₇₆H₁₁₅N₁₂O₁₆ requires 483.9513).

Compound F-13 ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((S)-2-((S)-2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamido)-3-methylbutanamido)-N-methyl-5-ureidopentanamido)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalanine 2,2,2-trifluoroacetate

Compound F-13-1: benzyl N-(4-((tert-butoxycarbonyl)(methyl)amino) phenethyl)-N-methyl-L-valinate

Compound 11C (250 mg, 0.567 mmol, 1 eq.) was dissolved in THF (10 ml) followed by the addition of NaH (60% suspension in mineral oil, 68 mg, 1.702 mmol, 3 eq.). The mixture was stirred for 5 minutes before adding iodomethane (106 μL, 1.702 mmol, 3 eq.). The reaction was stirred for 2 hours at room temperature before quenching with water and separating between EtOAc (100 mL) and water (50 mL). The organic phase was dried over MgSO₄ and evaporated to dryness to yield compound F-13-1 as a yellow oil (250 mg, 97%), which was used without further purification.

Compound F-13-2: benzyl N-methyl-N-(4-(methylamino)phenethyl)-L-valinate

Boc-protected aniline F-13-1 (250 mg, 0.550 mmol, 1 eq) was dissolved in MeOH (5 mL) followed by the addition of 1 mL of a commercially-available solution of HCl in ^(i)PrOH (5-6 M). The solution was stirred at room temperature for 2 hours before evaporating to dryness under reduced pressure. The resulting yellow oil was triturated with Et₂O to yield compound F-13-2 as a yellow solid (202 mg, 94%).

Compound F-13-3: benzyl N-(4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-N-methyl-5-ureidopentanamido)phenethyl)-N-methyl-L-valinate

Acid E-11-3 (190 mg, 0.508 mmol, 1.5 eq.) was dissolved in dry DMF (1 ml), followed by the addition of DIEA (118 μL, 0.677 mmol, 2 eq.), benzotriazol-1-yl-oxytripyrrolidinophosphonium hexafluorophosphate (PyBOP-264 mg, 0.508 mmol, 1.5 eq.) and aniline F-13-2 (120 mg, 0.339 mmol, 1 eq.). The mixture was stirred at room temperature overnight and the solvents evaporated under reduced pressure. The residue was purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound F-13-3 as a white solid (140 mg, 45%).

Compound F-13-4: N-(4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-N-methyl-5-ureidopentanamido)phenethyl)-N-methyl-L-valine

Compound F-13-3 (116 mg, 0.163 mmol, 1 eq.) was dissolved in MeOH (5 ml) in the presence of Pd/C 10% (30 mg) and hydrogenated for 2 hours at ambient temperature and atmospheric pressure. The reaction medium was filtered and concentrated under reduced pressure to yield 110 mg (99%) of compound F-13-4 as a beige solid.

Compound F-13-5: methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-N-methyl-5-ureidopentanamido)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate 2,2,2-trifluoroacetate

Amine 3D (89 mg, 0.140 mmol, 1 eq.) and acid F-13-4 (145 mg, 0.210 mmol, 1.5 eq.) were dissolved in dry DMF (4 mL), and PyBOP (109 mg, 0.210 mmol, 1.5 eq.) and DIEA (73 μL, 0.420 mmol, 3 eq.) were added. The mixture was stirred for 1 hour at room temperature and the solvent evaporated. The residue was separated between EtOAc and water, and the organic phase dried over MgSO₄, filtered and evaporated under reduced pressure. The crude product was purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound F-13-5 as a white solid (140 mg, 73%).

Compound F-13-6: ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-N-methyl-5-ureidopentanamido) phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalanine 2,2,2-trifluoroacetate

Compound F-13-5 (140 mg, 0.104 mmol, 1 eq.) was dissolved in a mixture of water (4 mL), acetonitrile (4 mL) and piperidine (2 mL) and stirred at room temperature for 4 hours. The solvent was evaporated under reduced pressure and the residue purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound F-13-6 as a white solid (115 mg, 83%).

Compound F-13

Compound F-13 was prepared according to the same method as for compound E-11, using Boc-protected amine F-13-6 (55 mg, 0.041 mmol, 1.0 eq.) in DCM (0.5 mL) and TFA (100 μL, 30 eq.), followed by dilution with DMF (1 mL), quenching with (DIEA (320 μL, 45 eq) then reaction with 2,5-dioxopyrrolidin-1-yl 6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoate (15 mg, 0.049 mmol, 1.2 eq.). After purification by preparative HPLC and lyophilisation, compound F-13 was obtained as a white solid (14 mg, 24%).

m/z (Q-TOF MS ESI+) 1314.8067 (2%, MH⁺, C₆₉H₁₀₈N₁₁O₁₄ requires 1314.8072), 657.9067 (100%, (MH₂)²⁺, C₆₉H₁₀₉N₁₁O₁₄ requires 657.9072).

Compound F-61 N—((S)-1-(((S)-1-((4-((3R,4S,7S,10S)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2-oxa-5,8,11-triazatridecan-13-yl)phenyl)amino)-1-oxo-5-ureidopentan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)-6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamide 2,2,2-trifluoroacetate

Compound F-61-1: benzyl N-(4-aminophenethyl)-N-methyl-L-valinate dihydrochloride

Compound 11C (1.0 g, 2.27 mmol, 1 eq.) was dissolved in 8 mL of a commercially-available solution of HCl in ^(i)PrOH (5-6 M). The mixture was stirred for 2 hours at room temperature before evaporating to dryness under reduced pressure. The residue was triturated twice with Et₂O (30 mL) and dried under vacuum to yield compound F-61-1 as a white solid (916 mg, 98%).

Compound F-61-2: benzyl N-(4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-5-ureidopentanamido)phenethyl)-N-methyl-L-valinate

Acid E-11-3 (769 mg, 2.05 mmol, 1.5 eq.) was dissolved in dry DMF (2.5 ml) followed by the addition of DIEA (957 μL, 5.48 mmol, 4 eq.) and PyBOP (1.07 g, 2.05 mmol, 1.5 eq.). Aniline F-61-1 (566 mg, 1.369 mmol, 1 eq.) was added and the mixture stirred at room temperature overnight. The solvents were evaporated under reduced pressure, and the residue purified on silica gel (DCM/MeOH) to yield 969 mg (102%) of compound F-61-2 as a white solid.

Compound F-61-3: N-(4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-5-ureidopentanamido)phenethyl)-N-methyl-L-valine

Compound F-61-2 (969 mg, 1.28 mmol, 1 eq.) was dissolved in MeOH (20 ml) in the presence of Pd/C 10% (270 mg) and hydrogenated for 3 hours at ambient temperature and atmospheric pressure. The reaction medium was filtered and concentrated under reduced pressure, and the residue purified on silica gel (DCM/MeOH/AcOH) to yield 520 mg (67%) of compound F-61-3 as a white solid.

Compound F-61-4: tert-butyl ((S)-1-(((S)-1-((4-((3R,4S,7S,10S)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2-oxa-5,8,11-triazatridecan-13-yl)phenyl)amino)-1-oxo-5-ureidopentan-2-yl)amino)-3-methyl-1-oxobutan-2-yl)carbamate 2,2,2-trifluoroacetate

Acid F-61-3 (67.5 mg, 0.111 mmol, 1.5 eq.) was dissolved in dry DMF (2 mL) and DECP (17 μL, 0.111 mmol, 1.5 eq.) and DIEA (39 μL, 0.223 mmol, 3 eq.) were added. After stirring for 15 minutes at room temperature, amine 1Y (50 mg, 0.074 mmol, 1 eq.) was added and the solution stirred overnight. The solvent was evaporated under reduced pressure, and the residue purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound F61-4 as a white solid (28 mg, 28%).

Compound F-61-5: (S)-2-((S)-2-amino-3-methylbutanamido)-N-(4-((3R,4S,7S,10S)-4-((S)-sec-butyl)-7,10-diisopropyl-3-(2-((S)-2-((1R,2R)-1-methoxy-2-methyl-3-oxo-3-(((S)-2-phenyl-1-(thiazol-2-yl)ethyl)amino)propyl)pyrrolidin-1-yl)-2-oxoethyl)-5,11-dimethyl-6,9-dioxo-2-oxa-5,8,11-triazatridecan-13-yl)phenyl)-5-ureidopentanamide bis(2,2,2-trifluoroacetate)

Compound F-61-4 (28 mg, 0.021 mmol, 1.0 eq.) was dissolved in TFA (200 μL). After 5 minutes, water (2 mL) and acetonitrile (0.5 mL) were added and the solution lyophilised overnight to yield compound F-61-5 as a colourless oil (38 mg, 134%).

Compound F-61

Compound F-61-5 (28.3 mg, 0.020 mmol, 1 eq.) was dissolved in acetonitrile (0.5 mL), followed by 2,5-dioxopyrrolidin-1-yl 6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoate (9 mg, 0.029 μmol, 1.4 eq.) and DIEA (25 μL, 0.143 mmol, 7 eq.). The mixture was stirred for 4.5 hours, after which time HPLC analysis showed the presence of starting material but complete consumption of the succinimide. Supplementary 2,5-dioxopyrrolidin-1-yl 6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoate was therefore added (3 mg, 0.01 μmol, 0.5 eq.) and the reaction stirred for 1.5 hours. HPLC analysis showed complete consumption of the starting material. The solvent was evaporated to dryness and the residue triturated twice with a mixture of EtOAc/Et₂O (80/20) to yield compound F-61 as an off-white solid (19.4 mg, 70%).

m/z (Q-TOF MS ESI+) 1361.7725 (2%, MNa⁺, C₇₀H₁₀₆N₁₂NaO₁₂S requires 1361.7666), 670.3961 (100%, (MH₂)²⁺, C₇₀H₁₀₈N₁₂O₁₂S requires 670.3960).

Compound F-62 methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((S)-2-((S)-2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamido)-3-methylbutanamido)-5-ureidopentanamido)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate 2,2,2-trifluoroacetate

Compound F-62-1: methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-5-ureidopentanamido)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate 2,2,2-trifluoroacetate

Compound F-62-1 was prepared in similar manner to compound F-61-4 from amine 3D (100 mg, 0.158 mmol, 0.9 eq.), acid F-61-3 (108 mg, 0.178 mmol, 1 eq.), DECP (41 μL, 0.267 mmol, 1.5 eq.) and DIEA (93 μL, 0.534 mmol, 3 eq.) in DMF (2 mL). After purification by preparative HPLC, compound F-62-1 was obtained as a white solid (93 mg, 39%).

Compound F-62-2: methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((S)-2-((S)-2-amino-3-methylbutanamido)-5-ureidopentanamido)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl) pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate bis(2,2,2-trifluoroacetate)

Compound F-62-1 (35 mg, 0.026 mmol, 1.0 eq.) was dissolved in TFA (200 μL). After 10 minutes, water (2 mL) and acetonitrile (0.5 mL) were added and the solution lyophilised overnight to yield compound F-62-2 as a white solid (34 mg, 105%).

Compound F-62

Amine F-62-2 (34 mg, 5.55 μmol, 1 eq.) was dissolved in acetonitrile (3 mL). DIEA (5 μL, 0.028 mmol, 5 eq.) and 2,5-dioxopyrrolidin-1-yl 6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoate (2 mg, 6.65 μmol, 1.2 eq.) were added. HPLC analysis showed complete consumption of the starting material. The solvent was evaporated to dryness and the residue triturated with a mixture of EtOAc/Et₂O (80/20). The crude product was purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound F-62 as a white solid (5.5 mg, 13%).

m/z (Q-TOF MS ESI+) 1336.7859 (2%, MNa⁺, C₆₉H₁₀₇N₁₁NaO14 requires 1336.7891), 657.9073 (100%, (MH₂)²⁺, C₆₉H₁₀₉N₁₁NaO₁₄ requires 657.9072).

Compound F-63 ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((S)-2-((S)-2-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamido)-3-methylbutanamido)-5-ureidopentanamido)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalanine 2,2,2-trifluoroacetate

Compound F-63-1: ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((S)-2-((S)-2-((tert-butoxycarbonyl)amino)-3-methylbutanamido)-5-ureidopentanamido)phenethyl) (methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl-L-nhenvlalanine

Compound F-62-1 (157 mg, 0.118 mmol, 1 eq.) was dissolved in a mixture of water (4.5 mL), acetonitrile (4.5 mL) and piperidine (3.5 mL) and stirred at room temperature for 5 hours. The solvent was evaporated under reduced pressure and the residue triturated Et₂O (60 mL). The solid was collected by filtration and rinsed twice with Et₂O (10 mL) to yield compound F-63-1 as an off-white solid (153 mg, 100%).

Compound F-63-2: ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-((S)-2-((S)-2-amino-3-methylbutanamido)-5-ureidopentanamido)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl) pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalanine bis 2,2,2-trifluoroacetate

Compound F-63-1 (153 mg, 0.127 mmol, 1.0 eq.) was dissolved in TFA (200 μL). After 10 minutes, water (2 mL) and acetonitrile (0.5 mL) were added and the solution lyophilised overnight to yield compound F-63-2 as a white solid (34 mg, 105%).

Compound F-63

Amine F-63-2 (100 mg, 0.082 mmol, 1 eq.) was dissolved in a mixture of acetonitrile (2 mL) and DMF (0.5 mL), and 2,5-dioxopyrrolidin-1-yl 6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoate (45 mg, 0.147 mmol, 1.8 eq.) and DIEA (71 μL, 0.409 mmol, 5 eq.) were added. After stirring at room temperature for 4.5 hours, the solvent was evaporated under reduced pressure. The crude product was purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound F-63 as a white solid after (42 mg, 36%).

m/z (Q-TOF MS ESI+) 1300.7901 (2%, MH⁺, C₆₈H₁₀₆N₁₁O₁₄ requires 1300.7915), 650.8990 (100%, (MH₂)²⁺, C₆₈H₁₀₇N₁₁O₁₄ requires 650.8994).

Compound G-12 methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-N-methylhexanamido)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate 2,2,2-trifluoroacetate

Compound G-12-1: benzyl N-(4-aminophenethyl)-N-methyl-L-valinate dihydrochloride

Into oxalyl chloride (3 mL) was dissolved 6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanoic acid (200 mg, 0.947 mmol, 1 eq.). The solution was stirred at room temperature for 5 hours before evaporating to dryness under reduced pressure. Compound G-12-1 was obtained as a beige solid (217 mg, 100%) and used in the next step without purification.

Compound G-12

Aniline 12 (40 mg, 0.045 mmol, 1 eq.) was dissolved in dry DCM (1 mL) at 0° C. and DIEA (8 μL, 0.045 mmol, 1 eq.) was added. After stirring for 30 minutes, a solution of compound G-12-1 (10 mg, 0.45 mmol, 1 eq.) in dry DCM (1 mL) was introduced and the reaction stirred for 1 hour at 0° C. The mixture was diluted with DCM (25 ml) and washed twice with water (20 mL), once with brine (10 mL). The organic phase was dried over Na₂SO₄, filtered and evaporated under reduced pressure to yield the crude product as a light brown solid (54 mg). This was purified by flash chromatography on silica gel (DCM/MeOH) followed by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The isolated product was lyophilised to yield a white solid (23 mg), which was repurified by preparative HPLC and the selected fractions combined and lyophilised to furnish compound G-12 as a white solid (9 mg, 16%).

m/z (Q-TOF MS ESI+) 1094.6543 (20%, MNa⁺, C₅₉H₈₉N₇NaO₁₁ requires 1094.6512), 1072.6722 (16%, MH⁺, C₅₉H₉₀N₇O₁₁i requires 1072.6693), 536.8358 (100%, (MH₂)²⁺, C₅₉H₉₁N₇O₁₁ requires 536.8383).

Compound G-13 ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((4-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)-N-methylhexanamido)phenethyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalanine 2,2,2-trifluoroacetate

Compound G-13

Aniline 13 (15 mg, 0.015 mmol, 1 eq.) was dissolved in dry DCM (1.5 mL) at 0° C. and DIEA (8 μL, 0.046 mmol, 3 eq.) was added. A solution of compound G-12-1 (3.5 mg, 0.046 mmol, 1 eq.) in dry DCM (0.5 mL) was introduced and the reaction stirred for 1.5 hours at 0° C. The solvent was evaporated under reduced pressure and the crude product purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound G-13 as a white solid (11.4 mg, 62%).

m/z (Q-TOF MS ESI+) 1058.6510 (30%, MH⁺, C₅₈H₈₈N₇O₁₁ requires 1058.6536), 529.8285 (100%, (MH₂)²⁺, C₅₈H₈₉N₇O₁₁ REQUIRES 529.8305).

Compound G-15 methyl ((2R,3R)-3-((S)-1-((3R,4S,5S)-4-((S)-2-((S)-2-((3-(6-(2,5-dioxo-2,5-dihydro-1H-pyrrol-1-yl)hexanamido)benzyl)(methyl)amino)-3-methylbutanamido)-N,3-dimethylbutanamido)-3-methoxy-5-methylheptanoyl)pyrrolidin-2-yl)-3-methoxy-2-methylpropanoyl)-L-phenylalaninate 2,2,2-trifluoroacetate

Compound G-15

Aniline 15 (40 mg, 0.047 mmol, 1 eq.) was dissolved in dry DCM (2 mL) at 0° C. and DIEA (10 μL, 0.056 mmol, 1.2 eq.) was added. A solution of compound G-12-1 (108 mg, 0.47 mmol, 10 eq.) in dry DCM (1 mL) was introduced and the reaction stirred for 1.5 hours at 0° C. The mixture was diluted with DCM (10 ml) and washed twice with water (5 mL). The organic phase was dried over MgSO₄, filtered and evaporated under reduced pressure to yield the crude product as a beige solid. This was purified by preparative HPLC (Waters 600E, SunFire Prep C18 OBD column, 5 μm, 19×100 mm; Eluting phase: water/MeCN buffered with 0.1% TFA; Gradient of 5% to 100% MeCN in 15 minutes; Waters 2487 UV Detector at 220 nm). The selected fractions were combined and lyophilised to furnish compound G15 as a white solid (27 mg, 50%).

m/z (Q-TOF MS ESI+) 1066.6517 (2%, MNa⁺, C₅₇H₈₅N₇NaO₁₁ requires 1066.6199), 522.8224 (100%, (MH₂)²⁺, C₅₇H₈₇N₇O₁₁ requires 522.8226).

Example 22: ADC Synthesis, Purification and Characterization

The procedure described below applies to chimeric and humanized IgGI forms. It must be understood that for any other forms, such as IgG2, IgG4, etc., the person skilled n the art would be capable of adapting this procedure using the general knowledge.

Antibodies (1-5 mg/ml) were partially reduced with Tris(2-carboxyethyl)phosphine hydrochloride (TCEP) in 10 mM borate buffer pH 8.4 containing 150 mM NaCl and 2 mM EDTA for 2 h at 37° C. Typically, 2.5-3 molar equivalents of TCEP were used to target a Drug-to-Antibody Ratios (DAR) of around 4, respectively. The partial antibody reduction was confirmed by SDS-PAGE analysis under non reducing conditions. Before Linker-Drug coupling to the released interchain cysteine residues, the reduction mixture was allowed to cool to room temperature. The antibody concentration was then adjusted to 1 mg/ml with 10 mM borate buffer pH 8.4 containing 150 mM NaCl and 2 mM EDTA, and a 5 molar excess of drug to antibody was added from a 10 mM solution in dimethyl sulfoxide (DMSO). The final DMSO concentration was adjusted to 10% to maintain the solubility of the drug in the aqueous medium during coupling. The reaction was carried out for 1 h at room temperature. The drug excess was quenched by addition of 1.5 moles of N-acetylcysteine per mole of drug and incubation for 1 h at room temperature. After dialysis against 25 mM His buffer pH 6.5 containing 150 mM NaCl overnight at 4° C., the antibody-drug-conjugates were purified by using methods known to persons skilled in the art based with commercial chromatography columns and ultrafiltration units. First, the non coupled drug and the ADC aggregates were eliminated by size exclusion chromatography (SEC) on S200 (GE Life Sciences) or TSK G3000 SW (Tosoh) column. The purified ADC monomers were then concentrated to 2-3 mg/ml by ultrafiltration on 30 or 50 kDa MWCO filtration units or by affinity chromatography on Protein A. The purified ADCs were stored at 4° C. after sterile filtration on 0.2 μm filter. They were further analyzed by SDS-PAGE under reducing and non reducing conditions to confirm drug conjugation and by SEC on analytical S200 or TSK G3000 SWXL columns to determine the content of monomers and aggregated forms. Protein concentrations were determined by using the bicinchoninic acid (BCA) assay with IgG as standard. The DAR was estimated for each purified ADC by HIC and LC-MS. Typically, the content of aggregated forms was lower than 5% and the DAR was comprised between 3.5 and 5.

Example 23: Cytotoxicity Evaluation of IGF-1R Antibodies Coupled with Different Drugs

The five IGF-1R antibodies were shown to be rapidly internalized into lysosomes and to have a lower binding capacity into acidic environments. In that respect, those Abs had all properties to be used as ADCs. Thus, the five chimeric anti-IGF-1R antibodies were coupled with three different compounds (G-13; E-13 and F-63). The drug antibody ratio of those ADCs was about 4. In order to evaluate the non specific cytotoxicity, an irrelevant chimeric antibody c9G4 was also coupled with those compounds at the same DAR. MCF-7 cells were incubated with increasing concentrations of each ADCs at 37° C. for 6 days in complete culture medium. Cell viability was assessed using a luminescent cell viability assay (CellTiter-Glo, Promega). Luminescent signal was read using a the Mithras plate reader (Berthold Technologies). The irrelevant chimeric antibody c9G4 coupled with either E-13, G-13 or F-63 showed no or modest cytotoxic activity on MCF-7 cells (FIG. 21 ). On the contrary, addition of all other ADCs obtained after coupling anti-IGF-1R antibodies with either E-13, G-13 or F-63 decreased dramatically MCF-7 cell viability.

Example 24: In Vivo Activity of the c208F2 Antibody Conjugated to Either E-13, G-13 or F-63 Compounds in the MCF-7 Xenocraft Model

In order to confirm that the in vitro efficacy of the c208F2 coupled to G-13, E-13 or F-63 compounds could be translated in vivo, they have been tested in the MCF-7 xenograft model.

All animal procedures were performed according to the guidelines of the 2010/63/UE Directive on the protection of animals used for scientific purposes. The protocol was approved by the Animal Ethical Committee of the Pierre Fabre Institute. Five millions MCF-7 cells were injected subcutaneous into 7 weeks old Swiss/Nude mice. Prior to cell injection, oestrogen pellets (Innovative Research of America) were implanted to the left flank to mice in order to release estrogens necessary to the in vivo growth of MCF-7 tumors.

Twenty days after MCF-7 cell implantation, when tumors reached an average size of 120-150 mm³, the animals were divided into groups of 5 mice according to tumor size and aspect. The different treatments were inoculated by intraperitoneal injections. The health status of animals was monitored daily. Tumor volume was measured twice a week with an electronic calliper until study end. Tumor volume is calculated with the following formula: π/6×length×width×height. Toxicity was evaluated following the weight of animals three times per week. Statistical analyses were performed at each measure using a Mann-Whitney test. All compounds were injected intraperitoneally (i.p.). In this example, the anti-tumor activity of c208F2 mAb coupled with either E-13, F-13 or F-63 at about DAR 4 was evaluated after 2 injections of a 7 mg/kg dose at D20 and D27 (FIGS. 22A, 22B and 22C). In parallel the capped-drug moieties E-13, F-13 and F-63 were injected at the equivalent dose of the one corresponding to 7 mg/kg of c208F2-E-13, c208F2-F-13 and c208F2-F-63 DAR about 4.

Injection of either c208-E-13 (FIG. 22A), c208F2-G-13 (FIG. 22B) or c208F2-F-63 (FIG. 22C) significantly inhibited and even induced a complete tumor growth regression (p<0.05 vs corresponding capped-drug). No statistical activity difference between c208-E-13, c208F2-G-13 and c208F2-F-63 could be noted. Capped drugs had no effect on MCF-7 tumor growth (p>0.05 vs control group)

A second set of experiments was performed with c208F2 coupled with either E-13 or G-13 and with the irrelevant antibody c9G4 coupled with either E-13 or G-13 in MCF-7 xenograft models as described previously. Mice were injected i.p. with 7 mg/kg of each ADCs at D20 and D27 (FIGS. 23A and 23B).

Injection of both c9G4-E-13 and c9G4-F-13 affected moderately and transiently the growth of MCF-7 xenograft tumors. However, this second experiment confirmed that injections of either c208-E-13 or c208F2-G-13 induced complete tumor regression since D43 showing the high anti-tumor activity of those ADCs.

Example 25: Potent Cytotoxicity In Vitro of Ax1 ADCs Coupled with Different Drugs

The cytotoxic activity of ADCs for inhibition of tumor cell growth was tested in a cell proliferation assay using SN12C (Ax1⁺ human renal cell carcinoma) and MCF-7 (Ax1⁻ human breast adenocarcinoma). Briefly, cells were seeded into 96 well multi-well plates the day before drug treatment at 2500 cells per well. ADCs and controls were serially diluted and then added to the mw-96 plates. Cells were then incubated for 6 days at 37° C. and 5% CO₂. The cell viability was quantified by measuring the level of ATP in the wells using the CellTiter-Glo® Luminescent Cell Viability Assay (Promega catalog #G7571). The percentage of cell viability was calculated considering untreated cells as 100%. Using a nonlinear regression analysis (GraphPad PRISM 4.0), the IC₅₀, the concentration of compound needed to yield a 50% reduction in viability compared with untreated cells (control=100%), was determined and expressed in molarity (FIG. 28 ).

Data showed in FIGS. 28A and 28B that hz1613F12 conjugated to either E-13 or G-13 give IC₅₀ values of 1.048 10⁻¹⁰ M, 1.413 10⁻¹⁰ M, respectively. Thus E-13 and G-13 can trigger a strong cytotocixity when coupled to an Ax1 antibody such as 1613F12. No cytotoxicity is observed on MCF7 cells (Ax1).

Example 26: In Vivo Activity of the Trastuzumab Antibody Conjugated to Either E-13 or G-13 Compounds in the Calu-3 Xenograft Model

In order to confirm the in vivo efficacy of antibodies coupled to G-13 or E-13 compounds, they have been coupled to Trastuzumab and tested in the HER2 sensitive xenograft model Calu-3 known for its HER2 amplification and (3⁺) expression. The antibody Tratuzumab was purchased from Euromedex, 24 Rue des Tuileries 67460 SOUFFELWEYERSHEIM/France.

All animal procedures were performed according to the guidelines of the 2010/63/UE Directive on the protection of animals used for scientific purposes. The protocol was approved by the Animal Ethical Committee of the Pierre Fabre Institute. Seven millions Calu-3 cells were injected subcutaneous into 7 weeks old SCID mice.

Six days after Calu-3 cell implantation, when tumors reached an average size of 250-260 mm³, the animals were divided into groups of 6 mice according to tumor size and aspect. The different treatments were inoculated by intraperitoneal injections. The health status of animals was monitored daily. Tumor volume was measured twice a week with an electronic calliper until study end. Tumor volume is calculated with the following formula: (length×width²)/2. Toxicity was evaluated following the weight of animals three times per week. Statistical analyses were performed at each measure using a Mann-Whitney test. All compounds were injected intraperitoneally (i.p.). In this example, the anti-tumor activity of Tratuzumab mAb coupled with either E-13 or G-13 at about DAR 4 was evaluated after 1 injections of a 3 mg/kg dose at D6. In parallel Trastuzumab alone was injected at the equivalent dose of the one corresponding to 3 mg/kg of naked antibody.

Injection of either Trastuzumab-E-13 (FIG. 29A) or Trastuzumab-G-13 (FIG. 29B) significantly inhibited the tumor growth and even induced a complete tumor growth regression in all treated mice (p<0.05 vs corresponding naked antibody). No statistical activity difference was observed between Trastuzumab-E-13, and Trastuzumab-G-13 groups. Compared to published data (Cretella et al. Molecular Cancer 2014, 13:143) on this Calu-3 model, TDM-1 did not induced complete regression even if its dosing was higher (15 mg/kg every 6 days vs 3 mg/kg, one injection respectively) than the one used for either Trastuzumab-E-13 or Trastuzumab-G-13.

Example 27: In Vivo Activity of the Trastuzumab Antibody Conjugated to Either E-13 or G-13 Compounds in the JIMT-1 Xenocraft Model

In order to know whether Trastuzumab antibody conjugates display also an activity on a model known to be resistant to Trastuzumab, the JIMT-1 xenograft model that highly expressed HER2 but that was resistant to Trastuzumab therapy was evaluated. All animal procedures were performed according to the guidelines of the 2010/63/UE Directive on the protection of animals used for scientific purposes. The protocol was approved by the Animal Ethical Committee of the Pierre Fabre Institute. Seven millions JIMT-1 cells were injected subcutaneous into 7 weeks old SCID mice.

Fourteen days after JIMT-1 cell implantation, when tumors reached an average size of 220-230 mm³, the animals were divided into groups of 5 mice according to tumor size and aspect. The different treatments were inoculated by intraperitoneal injections. The health status of animals was monitored daily. Tumor volume was measured twice a week with an electronic calliper until study end. Tumor volume is calculated with the following formula: (length×width²)/2. Toxicity was evaluated following the weight of animals three times per week. Statistical analyses were performed at each measure using a Mann-Whitney test. All compounds were injected intraperitoneally (i.p.). In this example, the anti-tumor activity of Trastuzumab mAb coupled with either E-13 or G-13 at about DAR 4 was evaluated after 1 injections of a 3 mg/kg dose at D6 (FIGS. 30A and 30B). In a first experiment, we have showed that Trastuzumab alone did not have any anti-tumoral effect (FIG. 30C). This result is in agreement with published data.

Injection of either Trastuzumab-E-13 (FIG. 30A) or Trastuzumab-G-13 (FIG. 30B) significantly inhibited the tumor growth traduced by respectively 73 and 70% of growth inhibition at day 34. No statistical activity difference could be noted between Trastuzumab-E-13, and Trastuzumab-G-13. As already observed in the Calu-3 model and compared to published data (Barok et al. Breast Cancer Research 2011, 13:R46) on this JIMT-1 model, TDM-1 seems to be less potent even if its dosing (15 mg/kg every 6 days vs 3 mg/kg, one injection respectively) was higher than the one used for either Trastuzumab-E-13 or Trastuzumab-G-13. 

The invention claimed is:
 1. A compound of the following formula:

or a pharmaceutically acceptable salt thereof, wherein: R₁ is H or OH, R₂ is a (C₁-C₆)alkyl, COOH, COO—(C₁-C₆)alkyl or thiazolyl group, R₃ is H or a (C₁-C₆)alkyl group, and H-A- is a group of formula H-A_(a)-A_(b)-, wherein A_(a) is NR₉ with R₉ being H or (C₁-C₆)alkyl, and A_(b) is linked to NR₃ and is: a (C₁-C₈)alkanediyl group, or a —(CH₂CH₂X₁)_(a1)(CH₂CH₂X₂)_(a2)(CH₂CH₂X₃)_(a3)(CH₂CH₂X₄)_(a4)CH₂CH₂— group with X₁, X₂, X₃ and X₄ each independently of one another representing O or NR₈; a1, a2, a3 and a4 each independently of one another representing 0 or 1 with a1+a2+a3+a4=1 or 2; and R₈ representing H or a (C₁-C₆)alkyl group.
 2. The compound according to claim 1, wherein: R₁ is OH and R₂ is a (C₁-C₆)alkyl group, or R₁ is H and R₂ is a COOH, COO—(C₁-C₆)alkyl or thiazolyl group.
 3. The compound according to claim 1, wherein R₁ is H and R₂ is COOH or COOMe.
 4. The compound according to claim 1, wherein R₃ is H or a methyl group.
 5. The compound according to claim 1, wherein H-A- is a group of formula H-A_(a)-A_(b)-, wherein A_(a) is NR₉ with R₉ being H or (C₁-C₆)alkyl, and A_(b) is linked to NR₃ and is: a (C₁-C₆)alkanediyl group, or a —(CH₂CH₂X₁)_(a1)(CH₂CH₂X₂)_(a2)CH₂CH₂— group with X₁ and X₂ each independently of one another representing O or NR₈; a1 and a2 each independently of one another representing 0 or 1 with a1+a2=1 or 2; and R₈ representing H or a (C₁-C₆)alkyl group.
 6. The compound according to claim 1, wherein the compound is selected from the group consisting of:


7. The compound according to claim 6, wherein the pharmaceutically acceptable salts are salts formed with trifluoroacetic acid.
 8. A method for preparing a compound according to claim 1 comprising a condensation reaction between a compound of formula (VI):

and a compound of formula (VII):

wherein: R₁ of the formula (VI) is H or OH, R₂ of the formula (VI) is a (C₁-C₆)alkyl, COOH COO—(C₁-C₆)alkyl or thiazolyl group, and wherein R₃ of the formula (VII) is H or a (C₁-C₆)alkyl group, R_(4a) of the formula (VII) is an H-A- group as defined in claim 1, and X is OH or Cl.
 9. A method for preparing a compound according to claim 1 comprising a substitution reaction between a compound of formula (VIII):

and a compound of formula (X): R_(4a)-Y  (X), wherein: R₁ of the formula (VIII) is H or OH, R₂ of the formula (VIII) is a (C₁-C₆)alkyl, COOH COO—(C₁-C₆)alkyl or thiazolyl group, and R₃ of the formula (VIII) is H or a (C₁-C₆)alkyl group, and wherein R_(4a) of the formula (X) is an H-A- group as defined in claim 1, and Y is a leaving group.
 10. A method for preparing a compound according to claim 1, wherein H-A- in the compound is a —CH₂R_(4b) group with R_(4b) being -A_(c)-A_(a)-H with A_(a) as defined in claim 1 and A_(c) being: a (C₁-C₇)alkanediyl group, or a —(CH₂CH₂X₁)_(a1)(CH₂CH₂X₂)_(a2)(CH₂CH₂X₃)_(a3)(CH₂CH₂X₄)_(a4)CH₂*— group with X₁, X₂, X₃, X₄, a1, a2, a3, and a4 as defined in claim 1, wherein the CH₂ group marked with an asterisk is linked to the CH₂ group of —CH₂R_(4b), wherein the method comprises a reductive amination reaction between a compound of formula (VIII):

and a compound of formula (XI): R_(4b)-CHO  (XI), wherein: R₁ of the formula (VIII) is H or OH, R₂ of the formula (VIII) is a (C₁-C₆)alkyl, COOH COO—(C₁-C₆)alkyl or thiazolyl group, and R₃ of the formula (VIII) is H or a (C₁-C₆)alkyl group, and wherein R_(4b) of the formula (XI) is -A_(c)-A_(a)-H as defined above. 